From 0360757ae86df1f30e43f8d171b043f18b75453d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ullrich=20Sch=C3=A4fer?= <hi+github@ullrich.is>
Date: Sun, 7 Jun 2026 17:47:22 +0200
Subject: [PATCH] =?UTF-8?q?feat(journal):=20Garmin=20activity=20import=20?=
 =?UTF-8?q?=E2=80=94=20provider,=20webhook=20pipeline,=20backfill=20(?=
 =?UTF-8?q?=C2=A71=E2=80=935)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Garmin Connect as the third connected-services provider (spec:
garmin-import). The interesting parts:

- Push-first ingestion: Garmin has no list endpoint. The webhook
  normalizes ping (callbackURL) and push (inline) notification batches
  into events; the slow work (authorized FIT download, FIT→GPX via the
  shared converter, activity creation) runs in a garmin-import-activity
  pg-boss job so the webhook answers fast. Callback URLs are validated
  against Garmin's API host before any fetch (SSRF guard).
- History via backfill requests: /sync/import/garmin is a date-range
  requester with honest async progress (no pick list — the concept
  doesn't exist in a push model). Ranges chunk to Garmin's 90-day cap;
  overlaps are free via sync_imports dedupe. Requests persist in
  import_batches via two new nullable columns (range_start/range_end).
- OAuth2 + PKCE on the existing oauth credential kind. Design
  correction from apply: the verifier rides a short-lived httpOnly
  cookie scoped to the callback path — the state param is visible in
  redirect URLs and must never carry it. Manifests opt in via pkce:true.
- Deregistration notifications flip the connection to 'revoked'
  (row kept for audit, imports retained, re-connect prompt shown).
- Framework evolutions, all additive: parseWebhook returns
  WebhookEvent[] (Garmin batches; Wahoo adapted), manifest gains
  configured()/importUrl/pkce, importActivity accepts summary stats
  for FIT-less imports, manager gains markRevoked.
- Env-gated: no GARMIN_CLIENT_ID → provider hidden on
  /settings/connections. Privacy manifest entry (DE+EN). i18n en+de.

Rollout (§6) stays gated on the Garmin Developer Program application
(submitted 2026-06-07). Fixtures are doc-shaped; the staging soak
swaps in recorded payloads if shapes differ.

Gate: typecheck ✓ lint ✓ unit+integration ✓ e2e 70/72 + both known
flakes green isolated ✓ openspec validate ✓

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 apps/journal/.env.example                     |   8 +
 .../app/jobs/garmin-import-activity.ts        |  33 +++
 .../app/lib/connected-services/manager.ts     |  12 ++
 .../connected-services/oauth-state.server.ts  |  36 ++++
 .../connected-services/oauth-state.test.ts    |  61 ++++++
 .../providers/garmin/backfill.test.ts         |  42 ++++
 .../providers/garmin/backfill.ts              | 111 ++++++++++
 .../providers/garmin/constants.ts             |   8 +
 .../providers/garmin/import.server.ts         |  82 ++++++++
 .../providers/garmin/manifest.test.ts         |  66 ++++++
 .../providers/garmin/manifest.ts              | 120 +++++++++++
 .../providers/garmin/webhook.test.ts          | 194 ++++++++++++++++++
 .../providers/garmin/webhook.ts               | 154 ++++++++++++++
 .../lib/connected-services/providers/index.ts |   4 +-
 .../providers/wahoo/webhook.test.ts           |  24 ++-
 .../providers/wahoo/webhook.ts                |  22 +-
 .../app/lib/connected-services/registry.ts    |  33 ++-
 apps/journal/app/lib/sync/imports.server.ts   |  18 +-
 apps/journal/app/routes.ts                    |   1 +
 .../app/routes/api.sync.callback.$provider.ts |  20 +-
 .../app/routes/api.sync.connect.$provider.ts  |  16 +-
 .../routes/api.sync.webhook.$provider.test.ts |   4 +-
 .../app/routes/api.sync.webhook.$provider.ts  |  14 +-
 apps/journal/app/routes/legal.privacy.tsx     |  23 ++-
 .../app/routes/settings.connections.server.ts |  25 ++-
 .../app/routes/settings.connections.tsx       |   2 +-
 .../app/routes/sync.import.garmin.server.ts   |  91 ++++++++
 .../journal/app/routes/sync.import.garmin.tsx | 112 ++++++++++
 apps/journal/server.ts                        |   3 +-
 infrastructure/docker-compose.staging.yml     |   2 +
 infrastructure/docker-compose.yml             |   4 +
 openspec/changes/garmin-import/design.md      |   2 +-
 openspec/changes/garmin-import/tasks.md       |  41 ++--
 packages/db/src/schema/journal.ts             |   5 +
 packages/i18n/src/locales/de.ts               |  23 +++
 packages/i18n/src/locales/en.ts               |  23 +++
 36 files changed, 1368 insertions(+), 71 deletions(-)
 create mode 100644 apps/journal/app/jobs/garmin-import-activity.ts
 create mode 100644 apps/journal/app/lib/connected-services/oauth-state.test.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/backfill.test.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/backfill.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/constants.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/import.server.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/manifest.test.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/manifest.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/webhook.test.ts
 create mode 100644 apps/journal/app/lib/connected-services/providers/garmin/webhook.ts
 create mode 100644 apps/journal/app/routes/sync.import.garmin.server.ts
 create mode 100644 apps/journal/app/routes/sync.import.garmin.tsx

diff --git a/apps/journal/.env.example b/apps/journal/.env.example
index ef8718a..8a51ed0 100644
--- a/apps/journal/.env.example
+++ b/apps/journal/.env.example
@@ -49,6 +49,14 @@
 # WAHOO_CLIENT_SECRET=
 # WAHOO_WEBHOOK_TOKEN=
 
+# Garmin Connect Developer Program credentials (spec: garmin-import).
+# Requires an approved program application; without these the Garmin
+# provider is hidden on /settings/connections. The OAuth callback to
+# register with Garmin is `<origin>/api/sync/callback/garmin`, the
+# notification endpoint `<origin>/api/sync/webhook/garmin`.
+# GARMIN_CLIENT_ID=
+# GARMIN_CLIENT_SECRET=
+
 # Integration test secret (only needed if running the integration
 # test suite that drives the API directly). Generate with
 # `openssl rand -hex 32`.
diff --git a/apps/journal/app/jobs/garmin-import-activity.ts b/apps/journal/app/jobs/garmin-import-activity.ts
new file mode 100644
index 0000000..edff614
--- /dev/null
+++ b/apps/journal/app/jobs/garmin-import-activity.ts
@@ -0,0 +1,33 @@
+import type { JobDefinition } from "@trails-cool/jobs";
+import { logger } from "../lib/logger.server.ts";
+import {
+  runGarminActivityImport,
+  type GarminImportData,
+} from "../lib/connected-services/providers/garmin/import.server.ts";
+
+// Garmin webhook notifications enqueue here (spec: garmin-import,
+// "Push-notification activity import"): the webhook answers 200
+// immediately and this job does the slow part — authorized file
+// download, FIT→GPX, activity creation. Backfill bursts deliver many
+// notifications at once; the queue absorbs them and pg-boss retries
+// transient download failures.
+export const garminImportActivityJob: JobDefinition = {
+  name: "garmin-import-activity",
+  retryLimit: 3,
+  expireInSeconds: 300,
+  async handler(jobs) {
+    const batch = Array.isArray(jobs) ? jobs : [jobs];
+    for (const job of batch) {
+      const data = job.data as GarminImportData;
+      try {
+        await runGarminActivityImport(data);
+      } catch (err) {
+        logger.warn(
+          { err, externalId: data.externalId },
+          "garmin-import-activity failed (pg-boss will retry)",
+        );
+        throw err;
+      }
+    }
+  },
+};
diff --git a/apps/journal/app/lib/connected-services/manager.ts b/apps/journal/app/lib/connected-services/manager.ts
index 511e3ae..706795f 100644
--- a/apps/journal/app/lib/connected-services/manager.ts
+++ b/apps/journal/app/lib/connected-services/manager.ts
@@ -168,6 +168,18 @@ export async function markNeedsRelink(
   console.warn(`[connected-services] ${serviceId} flipped to needs_relink: ${reason}`);
 }
 
+// Provider-side revocation (e.g. a Garmin deregistration notification):
+// keep the row for audit, flip to 'revoked' so every subsequent
+// withFreshCredentials short-circuits and the UI shows a re-connect
+// prompt. Imported activities are untouched.
+export async function markRevoked(serviceId: string): Promise<void> {
+  const db = getDb();
+  await db
+    .update(connectedServices)
+    .set({ status: "revoked" })
+    .where(eq(connectedServices.id, serviceId));
+}
+
 export async function updateGrantedScopes(
   serviceId: string,
   grantedScopes: string[],
diff --git a/apps/journal/app/lib/connected-services/oauth-state.server.ts b/apps/journal/app/lib/connected-services/oauth-state.server.ts
index fe886af..ae0fb8a 100644
--- a/apps/journal/app/lib/connected-services/oauth-state.server.ts
+++ b/apps/journal/app/lib/connected-services/oauth-state.server.ts
@@ -21,3 +21,39 @@ export function decodeOAuthState(raw: string | null | undefined): PushOAuthState
     return {};
   }
 }
+
+// --- PKCE (RFC 7636) ----------------------------------------------------
+//
+// Providers with `pkce: true` (Garmin) need a code verifier that survives
+// the connect → provider → callback redirect without ever appearing in a
+// URL (the whole point of PKCE is that the verifier stays out of the
+// authorization response). The `state` param is visible in redirects, so
+// the verifier rides a short-lived httpOnly cookie scoped to the callback
+// path instead.
+
+import { createHash, randomBytes } from "node:crypto";
+
+const PKCE_COOKIE = "__oauth_pkce";
+const PKCE_MAX_AGE_S = 600;
+
+export function generatePkcePair(): { verifier: string; challenge: string } {
+  // 32 random bytes → 43-char base64url verifier (within RFC 7636's 43–128).
+  const verifier = randomBytes(32).toString("base64url");
+  const challenge = createHash("sha256").update(verifier).digest("base64url");
+  return { verifier, challenge };
+}
+
+export function pkceCookieHeader(verifier: string): string {
+  const secure = process.env.NODE_ENV === "production" ? "; Secure" : "";
+  return `${PKCE_COOKIE}=${verifier}; Max-Age=${PKCE_MAX_AGE_S}; Path=/api/sync/callback; HttpOnly; SameSite=Lax${secure}`;
+}
+
+export function clearPkceCookieHeader(): string {
+  return `${PKCE_COOKIE}=; Max-Age=0; Path=/api/sync/callback; HttpOnly; SameSite=Lax`;
+}
+
+export function readPkceVerifier(request: Request): string | null {
+  const cookie = request.headers.get("Cookie") ?? "";
+  const match = cookie.match(new RegExp(`(?:^|;\\s*)${PKCE_COOKIE}=([^;]+)`));
+  return match?.[1] ?? null;
+}
diff --git a/apps/journal/app/lib/connected-services/oauth-state.test.ts b/apps/journal/app/lib/connected-services/oauth-state.test.ts
new file mode 100644
index 0000000..36d9f90
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/oauth-state.test.ts
@@ -0,0 +1,61 @@
+// PKCE helper tests (RFC 7636 S256) — spec: garmin-import, task 1.2.
+
+import { createHash } from "node:crypto";
+import { describe, it, expect } from "vitest";
+import {
+  generatePkcePair,
+  pkceCookieHeader,
+  readPkceVerifier,
+  clearPkceCookieHeader,
+  encodeOAuthState,
+  decodeOAuthState,
+} from "./oauth-state.server.ts";
+
+describe("generatePkcePair", () => {
+  it("produces an RFC 7636-compliant verifier and matching S256 challenge", () => {
+    const { verifier, challenge } = generatePkcePair();
+    expect(verifier.length).toBeGreaterThanOrEqual(43);
+    expect(verifier.length).toBeLessThanOrEqual(128);
+    expect(verifier).toMatch(/^[A-Za-z0-9_-]+$/); // base64url charset
+    const expected = createHash("sha256").update(verifier).digest("base64url");
+    expect(challenge).toBe(expected);
+  });
+
+  it("is unique per call", () => {
+    expect(generatePkcePair().verifier).not.toBe(generatePkcePair().verifier);
+  });
+});
+
+describe("PKCE cookie round trip", () => {
+  it("verifier set on connect is readable on callback", () => {
+    const { verifier } = generatePkcePair();
+    const setCookie = pkceCookieHeader(verifier);
+    // Browser reflects the cookie value back on the callback request.
+    const cookieValue = setCookie.split(";")[0]!;
+    const request = new Request("https://x.example/api/sync/callback/garmin", {
+      headers: { Cookie: `other=1; ${cookieValue}` },
+    });
+    expect(readPkceVerifier(request)).toBe(verifier);
+  });
+
+  it("returns null without the cookie; clear header expires it", () => {
+    const request = new Request("https://x.example/", { headers: { Cookie: "other=1" } });
+    expect(readPkceVerifier(request)).toBeNull();
+    expect(clearPkceCookieHeader()).toContain("Max-Age=0");
+  });
+
+  it("cookie is httpOnly and scoped to the callback path", () => {
+    const header = pkceCookieHeader("v");
+    expect(header).toContain("HttpOnly");
+    expect(header).toContain("Path=/api/sync/callback");
+  });
+});
+
+describe("oauth state encoding (pre-existing behavior)", () => {
+  it("round-trips and tolerates garbage", () => {
+    const encoded = encodeOAuthState({ returnTo: "/settings/connections" });
+    expect(decodeOAuthState(encoded)).toEqual({ returnTo: "/settings/connections" });
+    expect(decodeOAuthState("%%%not-base64%%%")).toEqual({});
+    expect(decodeOAuthState(null)).toEqual({});
+  });
+});
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/backfill.test.ts b/apps/journal/app/lib/connected-services/providers/garmin/backfill.test.ts
new file mode 100644
index 0000000..9c1be9e
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/backfill.test.ts
@@ -0,0 +1,42 @@
+// Unit tests for Garmin backfill chunking + request fan-out
+// (spec: garmin-import, "Historical import via backfill").
+
+import { describe, it, expect, vi } from "vitest";
+
+vi.mock("../../manager.ts", () => ({ withFreshCredentials: vi.fn() }));
+vi.mock("../../../db.ts", () => ({ getDb: () => ({}) }));
+
+const { chunkRange, BACKFILL_CHUNK_MS } = await import("./backfill.ts");
+
+const DAY = 24 * 60 * 60 * 1000;
+
+describe("chunkRange", () => {
+  it("returns a single chunk for ranges within the cap", () => {
+    const chunks = chunkRange(0, 30 * DAY);
+    expect(chunks).toEqual([{ fromMs: 0, toMs: 30 * DAY }]);
+  });
+
+  it("splits ranges larger than the cap, last chunk clamped", () => {
+    const chunks = chunkRange(0, 200 * DAY);
+    expect(chunks).toHaveLength(3);
+    expect(chunks[0]).toEqual({ fromMs: 0, toMs: BACKFILL_CHUNK_MS });
+    expect(chunks[2]!.toMs).toBe(200 * DAY);
+    // contiguous, no gaps or overlaps
+    expect(chunks[1]!.fromMs).toBe(chunks[0]!.toMs);
+    expect(chunks[2]!.fromMs).toBe(chunks[1]!.toMs);
+  });
+
+  it("returns [] for empty or inverted ranges", () => {
+    expect(chunkRange(5, 5)).toEqual([]);
+    expect(chunkRange(10, 5)).toEqual([]);
+  });
+
+  it("covers exactly the requested range at chunk boundaries", () => {
+    const chunks = chunkRange(0, 2 * BACKFILL_CHUNK_MS);
+    expect(chunks).toHaveLength(2);
+    expect(chunks[1]).toEqual({
+      fromMs: BACKFILL_CHUNK_MS,
+      toMs: 2 * BACKFILL_CHUNK_MS,
+    });
+  });
+});
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/backfill.ts b/apps/journal/app/lib/connected-services/providers/garmin/backfill.ts
new file mode 100644
index 0000000..1055a78
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/backfill.ts
@@ -0,0 +1,111 @@
+// Garmin historical import via the Activity API backfill endpoint
+// (spec: garmin-import, "Historical import via backfill").
+//
+// Garmin has no list-activities endpoint: you ask for a time range and
+// Garmin re-delivers those activities asynchronously through the same
+// notification pipeline the live webhook uses. Each accepted request
+// returns 202; the data arrives whenever Garmin gets to it.
+
+import { randomUUID } from "node:crypto";
+import { fetchWithTimeout } from "../../../http.server.ts";
+import { withFreshCredentials } from "../../manager.ts";
+import type { OAuthCredentials } from "../../types.ts";
+import { GARMIN_API } from "./constants.ts";
+
+// Garmin caps a single backfill request's window. 90 days per the
+// Activity API docs; if program onboarding reveals a different cap for
+// our key, this constant is the only thing to change (design.md, open
+// questions).
+export const BACKFILL_CHUNK_MS = 90 * 24 * 60 * 60 * 1000;
+
+const BACKFILL_URL = `${GARMIN_API}/wellness-api/rest/backfill/activities`;
+
+/**
+ * Split [from, to] into Garmin-sized chunks (inclusive bounds, ms).
+ * Returns [] for empty/inverted ranges.
+ */
+export function chunkRange(
+  fromMs: number,
+  toMs: number,
+  chunkMs: number = BACKFILL_CHUNK_MS,
+): Array<{ fromMs: number; toMs: number }> {
+  if (!(fromMs < toMs) || chunkMs <= 0) return [];
+  const chunks: Array<{ fromMs: number; toMs: number }> = [];
+  for (let start = fromMs; start < toMs; start += chunkMs) {
+    chunks.push({ fromMs: start, toMs: Math.min(start + chunkMs, toMs) });
+  }
+  return chunks;
+}
+
+export interface BackfillDeps {
+  requestChunk(
+    serviceId: string,
+    fromSec: number,
+    toSec: number,
+  ): Promise<void>;
+}
+
+function defaultDeps(): BackfillDeps {
+  return {
+    async requestChunk(serviceId, fromSec, toSec) {
+      await withFreshCredentials(serviceId, async (credentials) => {
+        const creds = credentials as OAuthCredentials;
+        const url = `${BACKFILL_URL}?summaryStartTimeInSeconds=${fromSec}&summaryEndTimeInSeconds=${toSec}`;
+        const resp = await fetchWithTimeout(url, {
+          headers: { Authorization: `Bearer ${creds.access_token}` },
+        });
+        // 202 = accepted. 409 = an identical/overlapping request is
+        // already in flight — fine, the data will arrive either way
+        // and sync_imports dedupes.
+        if (!resp.ok && resp.status !== 409) {
+          const text = await resp.text().catch(() => "");
+          throw new Error(`Garmin backfill request failed: ${resp.status} ${text}`);
+        }
+      });
+    },
+  };
+}
+
+/**
+ * Issue backfill requests covering [from, to] and persist one
+ * import_batches row describing the whole request (progress UX reads
+ * it back on the import page).
+ */
+export async function requestBackfill(
+  service: { id: string; userId: string },
+  from: Date,
+  to: Date,
+  deps: BackfillDeps = defaultDeps(),
+): Promise<{ batchId: string; chunks: number }> {
+  const chunks = chunkRange(from.getTime(), to.getTime());
+  if (chunks.length === 0) throw new Error("Empty backfill range");
+
+  for (const chunk of chunks) {
+    await deps.requestChunk(
+      service.id,
+      Math.floor(chunk.fromMs / 1000),
+      Math.floor(chunk.toMs / 1000),
+    );
+  }
+
+  // Record the request for the import page. Lazy import keeps the DB
+  // out of this module's graph for pure-function tests (chunkRange).
+  const { getDb } = await import("../../../db.ts");
+  const { importBatches } = await import("@trails-cool/db/schema/journal");
+  const batchId = randomUUID();
+  await getDb()
+    .insert(importBatches)
+    .values({
+      id: batchId,
+      userId: service.userId,
+      connectionId: service.id,
+      provider: "garmin",
+      // Garmin delivers asynchronously — the batch is "running" from
+      // our perspective until the operator-facing page stops caring.
+      // totalFound is unknowable up front (no list endpoint).
+      status: "running",
+      rangeStart: from,
+      rangeEnd: to,
+    });
+  return { batchId, chunks: chunks.length };
+}
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/constants.ts b/apps/journal/app/lib/connected-services/providers/garmin/constants.ts
new file mode 100644
index 0000000..955a191
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/constants.ts
@@ -0,0 +1,8 @@
+// Garmin endpoint constants — own module so manifest.ts, webhook.ts,
+// import.server.ts, and backfill.ts can all use them without forming
+// an import cycle (manifest → webhook → import.server must never loop
+// back into manifest for a value needed at module-eval time).
+
+export const GARMIN_API = "https://apis.garmin.com";
+export const GARMIN_AUTHORIZE = "https://connect.garmin.com/oauth2Confirm";
+export const GARMIN_TOKEN = "https://diauth.garmin.com/di-oauth2-service/oauth/token";
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/import.server.ts b/apps/journal/app/lib/connected-services/providers/garmin/import.server.ts
new file mode 100644
index 0000000..6c9f439
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/import.server.ts
@@ -0,0 +1,82 @@
+// Garmin activity import — the slow half of the webhook pipeline.
+// Runs inside the `garmin-import-activity` pg-boss job: download the
+// activity file from the notification's callback URL (Authorized via
+// the user's token), convert to GPX, create the activity, record the
+// dedupe row. Stats-only when there is no file.
+
+import { fitToGpx } from "../../fit.ts";
+import { fetchWithTimeout } from "../../../http.server.ts";
+import { isAlreadyImported, importActivity } from "../../../sync/imports.server.ts";
+import { getServiceById, withFreshCredentials } from "../../manager.ts";
+import type { OAuthCredentials } from "../../types.ts";
+import { logger } from "../../../logger.server.ts";
+import { GARMIN_API } from "./constants.ts";
+
+// SSRF guard: notification callback URLs are attacker-controllable
+// input until proven otherwise — only Garmin's API host is fetchable.
+const ALLOWED_CALLBACK_HOSTS = new Set([new URL(GARMIN_API).host]);
+
+export function isAllowedGarminCallback(url: string): boolean {
+  try {
+    const parsed = new URL(url);
+    return parsed.protocol === "https:" && ALLOWED_CALLBACK_HOSTS.has(parsed.host);
+  } catch {
+    return false;
+  }
+}
+
+export interface GarminImportData {
+  serviceId: string;
+  userId: string;
+  externalId: string;
+  callbackUrl: string | null;
+  fileType: string | null;
+  name: string | null;
+  startedAt: string | null;
+  duration: number | null;
+  distance: number | null;
+}
+
+export async function runGarminActivityImport(data: GarminImportData): Promise<void> {
+  // Connection may have been revoked/relinked between enqueue and run.
+  const service = await getServiceById(data.serviceId);
+  if (!service || service.status !== "active") {
+    logger.info({ serviceId: data.serviceId }, "garmin import: connection not active — skipped");
+    return;
+  }
+
+  if (await isAlreadyImported(data.userId, "garmin", data.externalId)) return;
+
+  let gpx: string | undefined;
+  if (data.callbackUrl && isAllowedGarminCallback(data.callbackUrl)) {
+    const buffer = await withFreshCredentials(service.id, async (credentials) => {
+      const creds = credentials as OAuthCredentials;
+      const resp = await fetchWithTimeout(data.callbackUrl!, {
+        headers: { Authorization: `Bearer ${creds.access_token}` },
+      });
+      if (!resp.ok) {
+        throw new Error(`Garmin file download failed: ${resp.status}`);
+      }
+      return Buffer.from(await resp.arrayBuffer());
+    });
+    if (data.fileType === "GPX") {
+      // Garmin can serve GPX directly; createActivity validates it.
+      gpx = buffer.toString("utf8");
+    } else {
+      // FIT (default) — shared provider-agnostic converter.
+      gpx = (await fitToGpx(buffer, data.name ?? "Garmin activity")) ?? undefined;
+    }
+  }
+
+  await importActivity(data.userId, "garmin", data.externalId, {
+    name: data.name ?? "Garmin activity",
+    gpx,
+    distance: data.distance,
+    duration: data.duration,
+    startedAt: data.startedAt ? new Date(data.startedAt) : null,
+  });
+  logger.info(
+    { externalId: data.externalId, hadFile: !!gpx },
+    "garmin import: activity imported",
+  );
+}
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/manifest.test.ts b/apps/journal/app/lib/connected-services/providers/garmin/manifest.test.ts
new file mode 100644
index 0000000..531f181
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/manifest.test.ts
@@ -0,0 +1,66 @@
+// Manifest contract tests (spec: garmin-import, "Connect Garmin
+// account" + PKCE parameters + env gating).
+
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
+
+vi.mock("../../manager.ts", () => ({
+  getServiceByProviderUser: vi.fn(),
+  markRevoked: vi.fn(),
+  getServiceById: vi.fn(),
+  withFreshCredentials: vi.fn(),
+}));
+vi.mock("../../../boss.server.ts", () => ({ enqueueOptional: vi.fn() }));
+vi.mock("../../../sync/imports.server.ts", () => ({
+  isAlreadyImported: vi.fn(),
+  importActivity: vi.fn(),
+}));
+vi.mock("../../../db.ts", () => ({ getDb: () => ({}) }));
+
+const { garminManifest } = await import("./manifest.ts");
+
+const ENV_KEYS = ["GARMIN_CLIENT_ID", "GARMIN_CLIENT_SECRET"] as const;
+const saved: Record<string, string | undefined> = {};
+
+beforeEach(() => {
+  for (const k of ENV_KEYS) saved[k] = process.env[k];
+});
+afterEach(() => {
+  for (const k of ENV_KEYS) {
+    if (saved[k] === undefined) delete process.env[k];
+    else process.env[k] = saved[k];
+  }
+});
+
+describe("garminManifest", () => {
+  it("declares oauth + PKCE, no pick-list importer, custom import page", () => {
+    expect(garminManifest.id).toBe("garmin");
+    expect(garminManifest.credentialKind).toBe("oauth");
+    expect(garminManifest.pkce).toBe(true);
+    expect(garminManifest.importer).toBeUndefined();
+    expect(garminManifest.importUrl).toBe("/sync/import/garmin");
+    expect(garminManifest.webhookReceiver).toBeDefined();
+  });
+
+  it("is hidden without instance credentials, shown with them", () => {
+    delete process.env.GARMIN_CLIENT_ID;
+    expect(garminManifest.configured!()).toBe(false);
+    process.env.GARMIN_CLIENT_ID = "test-client";
+    expect(garminManifest.configured!()).toBe(true);
+  });
+
+  it("buildAuthUrl carries the S256 code challenge", () => {
+    process.env.GARMIN_CLIENT_ID = "test-client";
+    const url = new URL(
+      garminManifest.buildAuthUrl!(
+        "https://journal.example/api/sync/callback/garmin",
+        "state-123",
+        { codeChallenge: "challenge-abc" },
+      ),
+    );
+    expect(url.origin + url.pathname).toBe("https://connect.garmin.com/oauth2Confirm");
+    expect(url.searchParams.get("client_id")).toBe("test-client");
+    expect(url.searchParams.get("code_challenge")).toBe("challenge-abc");
+    expect(url.searchParams.get("code_challenge_method")).toBe("S256");
+    expect(url.searchParams.get("state")).toBe("state-123");
+  });
+});
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/manifest.ts b/apps/journal/app/lib/connected-services/providers/garmin/manifest.ts
new file mode 100644
index 0000000..c9a9398
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/manifest.ts
@@ -0,0 +1,120 @@
+// Garmin provider manifest (spec: garmin-import). OAuth2 + PKCE on the
+// shared oauth credential adapter — PKCE is a handshake detail (see
+// design.md), the stored blob is plain OAuthCredentials.
+//
+// Garmin is push-first: there is no list-activities endpoint, so this
+// manifest declares no `importer`. Ingestion happens via the webhook
+// receiver (ping/push notifications) and history via backfill requests
+// (see backfill.ts + the /sync/import/garmin page).
+//
+// Endpoint references: Garmin Connect Developer Program, Activity API.
+// Exact notification shapes are normalized tolerantly in webhook.ts —
+// Garmin's docs shift between API versions (design.md, Risks).
+
+import { oauthCredentialAdapter } from "../../credential-adapters/oauth.ts";
+import type { ProviderManifest } from "../../registry.ts";
+import type { OAuthCredentials, ProviderOAuthConfig } from "../../types.ts";
+import { garminWebhook } from "./webhook.ts";
+import { GARMIN_API, GARMIN_AUTHORIZE, GARMIN_TOKEN } from "./constants.ts";
+
+function clientId(): string {
+  return process.env.GARMIN_CLIENT_ID ?? "";
+}
+function clientSecret(): string {
+  return process.env.GARMIN_CLIENT_SECRET ?? "";
+}
+
+const oauthConfig: ProviderOAuthConfig = {
+  get tokenUrl() {
+    return GARMIN_TOKEN;
+  },
+  get clientId() {
+    return clientId();
+  },
+  get clientSecret() {
+    return clientSecret();
+  },
+};
+
+export const garminManifest: ProviderManifest = {
+  id: "garmin",
+  displayName: "Garmin",
+  credentialKind: "oauth",
+  credentialAdapter: oauthCredentialAdapter as ProviderManifest["credentialAdapter"],
+  oauthConfig,
+  pkce: true,
+  // No instance credentials → no Garmin row on the connections page.
+  // (Garmin program keys are per-operator; self-hosted instances
+  // without one must not render a dead Connect button.)
+  configured: () => clientId().length > 0,
+  // Backfill requester, not a pick list — Garmin has no list endpoint.
+  importUrl: "/sync/import/garmin",
+
+  buildAuthUrl(redirectUri, state, extras): string {
+    const params = new URLSearchParams({
+      client_id: clientId(),
+      response_type: "code",
+      redirect_uri: redirectUri,
+      state,
+    });
+    if (extras?.codeChallenge) {
+      params.set("code_challenge", extras.codeChallenge);
+      params.set("code_challenge_method", "S256");
+    }
+    return `${GARMIN_AUTHORIZE}?${params}`;
+  },
+
+  async exchangeCode(
+    code,
+    redirectUri,
+    extras,
+  ): Promise<{
+    credentials: OAuthCredentials;
+    providerUserId: string | null;
+    grantedScopes: string[];
+  }> {
+    const resp = await fetch(GARMIN_TOKEN, {
+      method: "POST",
+      headers: { "Content-Type": "application/x-www-form-urlencoded" },
+      body: new URLSearchParams({
+        grant_type: "authorization_code",
+        client_id: clientId(),
+        client_secret: clientSecret(),
+        code,
+        code_verifier: extras?.codeVerifier ?? "",
+        redirect_uri: redirectUri,
+      }).toString(),
+    });
+    if (!resp.ok) {
+      const text = await resp.text().catch(() => "");
+      throw new Error(`Garmin token exchange failed: ${resp.status} ${text}`);
+    }
+    const data = (await resp.json()) as {
+      access_token: string;
+      refresh_token: string;
+      expires_in: number;
+      scope?: string;
+    };
+
+    // Garmin user id — needed to route webhook notifications to the
+    // right local user.
+    const userResp = await fetch(`${GARMIN_API}/wellness-api/rest/user/id`, {
+      headers: { Authorization: `Bearer ${data.access_token}` },
+    });
+    const user = userResp.ok
+      ? ((await userResp.json()) as { userId?: string })
+      : null;
+
+    return {
+      credentials: {
+        access_token: data.access_token,
+        refresh_token: data.refresh_token,
+        expires_at: new Date(Date.now() + data.expires_in * 1000).toISOString(),
+      },
+      providerUserId: user?.userId ?? null,
+      grantedScopes: data.scope ? data.scope.split(" ") : [],
+    };
+  },
+
+  webhookReceiver: garminWebhook,
+};
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/webhook.test.ts b/apps/journal/app/lib/connected-services/providers/garmin/webhook.test.ts
new file mode 100644
index 0000000..c360717
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/webhook.test.ts
@@ -0,0 +1,194 @@
+// Contract tests for the Garmin WebhookReceiver (spec: garmin-import).
+//
+// Seam: parseWebhook(body) -> WebhookEvent[] (Garmin batches notifications)
+//       handle(event) -> void (enqueues the import job; deregistration
+//       revokes; SSRF-suspicious callback URLs are dropped)
+
+import { describe, it, expect, beforeEach, vi } from "vitest";
+
+const mockGetServiceByProviderUser = vi.fn();
+const mockMarkRevoked = vi.fn();
+const mockEnqueueOptional = vi.fn();
+
+vi.mock("../../manager.ts", () => ({
+  getServiceByProviderUser: mockGetServiceByProviderUser,
+  markRevoked: mockMarkRevoked,
+  // imported transitively via import.server.ts
+  getServiceById: vi.fn(),
+  withFreshCredentials: vi.fn(),
+}));
+vi.mock("../../../boss.server.ts", () => ({
+  enqueueOptional: mockEnqueueOptional,
+}));
+vi.mock("../../../sync/imports.server.ts", () => ({
+  isAlreadyImported: vi.fn(),
+  importActivity: vi.fn(),
+}));
+vi.mock("../../../db.ts", () => ({ getDb: () => ({}) }));
+
+beforeEach(() => {
+  mockGetServiceByProviderUser.mockReset();
+  mockMarkRevoked.mockReset();
+  mockEnqueueOptional.mockReset();
+});
+
+const { garminWebhook } = await import("./webhook.ts");
+const { isAllowedGarminCallback } = await import("./import.server.ts");
+
+describe("garminWebhook.parseWebhook", () => {
+  it("parses a ping-style activityFiles batch into file events", () => {
+    const events = garminWebhook.parseWebhook({
+      activityFiles: [
+        {
+          userId: "g-user-1",
+          summaryId: "s-1",
+          activityId: 1001,
+          activityName: "Morning Run",
+          callbackURL: "https://apis.garmin.com/wellness-api/rest/activityFile?id=1001",
+          fileType: "FIT",
+          startTimeInSeconds: 1780000000,
+          durationInSeconds: 3600,
+          distanceInMeters: 10000,
+        },
+      ],
+    });
+    expect(events).toHaveLength(1);
+    expect(events[0]).toMatchObject({
+      eventType: "garmin:activity-file",
+      providerUserId: "g-user-1",
+      workoutId: "1001",
+      fileUrl: expect.stringContaining("apis.garmin.com"),
+      name: "Morning Run",
+      duration: 3600,
+      distance: 10000,
+      fileType: "FIT",
+    });
+  });
+
+  it("parses push-style activity summaries (FIT-less, stats-only path)", () => {
+    const events = garminWebhook.parseWebhook({
+      activities: [
+        {
+          userId: "g-user-1",
+          summaryId: "s-2",
+          activityId: 1002,
+          activityName: "Indoor Row",
+          durationInSeconds: 1800,
+        },
+      ],
+    });
+    expect(events).toHaveLength(1);
+    expect(events[0]).toMatchObject({
+      eventType: "garmin:activity-summary",
+      workoutId: "1002",
+      duration: 1800,
+    });
+    expect(events[0]!.fileUrl).toBeUndefined();
+  });
+
+  it("parses deregistrations", () => {
+    const events = garminWebhook.parseWebhook({
+      deregistrations: [{ userId: "g-user-1" }],
+    });
+    expect(events).toEqual([
+      {
+        eventType: "garmin:deregistration",
+        providerUserId: "g-user-1",
+        workoutId: "",
+      },
+    ]);
+  });
+
+  it("handles mixed batches and skips malformed entries", () => {
+    const events = garminWebhook.parseWebhook({
+      activityFiles: [
+        { userId: "u1", activityId: 1 },
+        { activityId: 2 }, // no userId — skipped
+        { userId: "u3" }, // no id — skipped
+      ],
+      deregistrations: [{}, { userId: "u4" }],
+      somethingGarminAddedLater: [{ userId: "u5" }],
+    });
+    expect(events.map((e) => e.eventType)).toEqual([
+      "garmin:activity-file",
+      "garmin:deregistration",
+    ]);
+  });
+
+  it("returns no events for non-object bodies", () => {
+    expect(garminWebhook.parseWebhook(null)).toEqual([]);
+    expect(garminWebhook.parseWebhook("x")).toEqual([]);
+  });
+});
+
+describe("garminWebhook.handle", () => {
+  const service = { id: "svc-g1", userId: "u1", provider: "garmin" };
+
+  it("enqueues the import job for a known user's file event", async () => {
+    mockGetServiceByProviderUser.mockResolvedValue(service);
+
+    await garminWebhook.handle({
+      eventType: "garmin:activity-file",
+      providerUserId: "g-user-1",
+      workoutId: "1001",
+      fileUrl: "https://apis.garmin.com/wellness-api/rest/activityFile?id=1001",
+      fileType: "FIT",
+      name: "Morning Run",
+    });
+
+    expect(mockEnqueueOptional).toHaveBeenCalledWith(
+      "garmin-import-activity",
+      expect.objectContaining({
+        serviceId: "svc-g1",
+        userId: "u1",
+        externalId: "1001",
+        callbackUrl: expect.stringContaining("apis.garmin.com"),
+        fileType: "FIT",
+      }),
+      expect.anything(),
+    );
+  });
+
+  it("silently skips unknown users (no leak)", async () => {
+    mockGetServiceByProviderUser.mockResolvedValue(null);
+    await garminWebhook.handle({
+      eventType: "garmin:activity-file",
+      providerUserId: "nobody",
+      workoutId: "1",
+    });
+    expect(mockEnqueueOptional).not.toHaveBeenCalled();
+    expect(mockMarkRevoked).not.toHaveBeenCalled();
+  });
+
+  it("drops events whose callback URL is not Garmin's API host (SSRF guard)", async () => {
+    mockGetServiceByProviderUser.mockResolvedValue(service);
+    await garminWebhook.handle({
+      eventType: "garmin:activity-file",
+      providerUserId: "g-user-1",
+      workoutId: "1001",
+      fileUrl: "https://attacker.example/steal?token=",
+    });
+    expect(mockEnqueueOptional).not.toHaveBeenCalled();
+  });
+
+  it("revokes the connection on deregistration", async () => {
+    mockGetServiceByProviderUser.mockResolvedValue(service);
+    await garminWebhook.handle({
+      eventType: "garmin:deregistration",
+      providerUserId: "g-user-1",
+      workoutId: "",
+    });
+    expect(mockMarkRevoked).toHaveBeenCalledWith("svc-g1");
+    expect(mockEnqueueOptional).not.toHaveBeenCalled();
+  });
+});
+
+describe("isAllowedGarminCallback", () => {
+  it("allows only https URLs on Garmin's API host", () => {
+    expect(isAllowedGarminCallback("https://apis.garmin.com/wellness-api/rest/x")).toBe(true);
+    expect(isAllowedGarminCallback("http://apis.garmin.com/x")).toBe(false);
+    expect(isAllowedGarminCallback("https://apis.garmin.com.evil.example/x")).toBe(false);
+    expect(isAllowedGarminCallback("https://evil.example/apis.garmin.com")).toBe(false);
+    expect(isAllowedGarminCallback("not a url")).toBe(false);
+  });
+});
diff --git a/apps/journal/app/lib/connected-services/providers/garmin/webhook.ts b/apps/journal/app/lib/connected-services/providers/garmin/webhook.ts
new file mode 100644
index 0000000..aded436
--- /dev/null
+++ b/apps/journal/app/lib/connected-services/providers/garmin/webhook.ts
@@ -0,0 +1,154 @@
+// Garmin WebhookReceiver capability adapter (spec: garmin-import,
+// "Push-notification activity import" + "Deregistration handling").
+//
+// Garmin POSTs notifications to /api/sync/webhook/garmin in batches:
+// - `activityFiles`: ping-style entries with a callbackURL to a FIT/GPX
+//   file (the main import path)
+// - `activities` / `activityDetails`: summary entries (stats; used for
+//   FIT-less activities)
+// - `deregistrations`: the user revoked access on Garmin's side
+//
+// The webhook must answer fast (Garmin retries and throttles slow
+// consumers), so `handle` only validates + enqueues; the download and
+// FIT→GPX conversion happen in the `garmin-import-activity` pg-boss job
+// (same lesson as federation's inbox: never do slow work in an inbound
+// hook). Deregistrations are the exception — a single UPDATE is cheap
+// and must not be lost to a queue hiccup.
+//
+// Notification shapes are under-documented and drift between Garmin API
+// versions, so parsing is tolerant: unknown keys are ignored, malformed
+// entries are skipped, and nothing here ever throws on bad input.
+
+import { logger } from "../../../logger.server.ts";
+import { enqueueOptional } from "../../../boss.server.ts";
+import { getServiceByProviderUser, markRevoked } from "../../manager.ts";
+import type { WebhookEvent, WebhookReceiver } from "../../registry.ts";
+import { isAllowedGarminCallback } from "./import.server.ts";
+
+interface GarminNotificationEntry {
+  userId?: string;
+  summaryId?: string | number;
+  activityId?: string | number;
+  activityName?: string;
+  activityType?: string;
+  callbackURL?: string;
+  fileType?: string;
+  startTimeInSeconds?: number;
+  durationInSeconds?: number;
+  distanceInMeters?: number;
+}
+
+interface GarminWebhookBody {
+  activityFiles?: GarminNotificationEntry[];
+  activities?: GarminNotificationEntry[];
+  activityDetails?: GarminNotificationEntry[];
+  deregistrations?: { userId?: string }[];
+}
+
+const EVENT_FILE = "garmin:activity-file";
+const EVENT_SUMMARY = "garmin:activity-summary";
+const EVENT_DEREGISTRATION = "garmin:deregistration";
+
+function externalId(entry: GarminNotificationEntry): string {
+  const id = entry.activityId ?? entry.summaryId;
+  return id == null ? "" : String(id);
+}
+
+function entryToEvent(
+  entry: GarminNotificationEntry,
+  eventType: string,
+): WebhookEvent | null {
+  if (!entry.userId || !externalId(entry)) return null;
+  return {
+    eventType,
+    providerUserId: entry.userId,
+    workoutId: externalId(entry),
+    fileUrl: entry.callbackURL,
+    name: entry.activityName,
+    startedAt:
+      entry.startTimeInSeconds != null
+        ? new Date(entry.startTimeInSeconds * 1000).toISOString()
+        : undefined,
+    duration: entry.durationInSeconds ?? null,
+    distance: entry.distanceInMeters ?? null,
+    fileType: entry.fileType,
+  };
+}
+
+export const garminWebhook: WebhookReceiver = {
+  parseWebhook(body: unknown): WebhookEvent[] {
+    if (typeof body !== "object" || body === null) return [];
+    const payload = body as GarminWebhookBody;
+    const events: WebhookEvent[] = [];
+
+    for (const entry of payload.activityFiles ?? []) {
+      const event = entryToEvent(entry, EVENT_FILE);
+      if (event) events.push(event);
+    }
+    // Summaries cover FIT-less activities (stats-only import). A FIT
+    // notification for the same activityId wins via sync_imports dedupe
+    // ordering being first-come — both paths import once.
+    for (const entry of [...(payload.activities ?? []), ...(payload.activityDetails ?? [])]) {
+      const event = entryToEvent(entry, EVENT_SUMMARY);
+      if (event) events.push(event);
+    }
+    for (const dereg of payload.deregistrations ?? []) {
+      if (dereg.userId) {
+        events.push({
+          eventType: EVENT_DEREGISTRATION,
+          providerUserId: dereg.userId,
+          workoutId: "",
+        });
+      }
+    }
+    return events;
+  },
+
+  async handle(event: WebhookEvent): Promise<void> {
+    // Unknown users: silent 200 — never reveal user existence.
+    const service = await getServiceByProviderUser("garmin", event.providerUserId);
+    if (!service) return;
+
+    if (event.eventType === EVENT_DEREGISTRATION) {
+      // Spec: provider-side revocation keeps the row (audit) but stops
+      // every subsequent Garmin call for this user.
+      await markRevoked(service.id);
+      logger.info({ serviceId: service.id }, "garmin: deregistration — connection revoked");
+      return;
+    }
+
+    // SSRF guard: a callback URL that doesn't point at Garmin's API is
+    // dropped here, before it can ever be fetched (design.md, Risks).
+    if (event.fileUrl && !isAllowedGarminCallback(event.fileUrl)) {
+      logger.warn(
+        { host: safeHost(event.fileUrl) },
+        "garmin: notification callback URL not on the Garmin allowlist — dropped",
+      );
+      return;
+    }
+
+    await enqueueOptional(
+      "garmin-import-activity",
+      {
+        serviceId: service.id,
+        userId: service.userId,
+        externalId: event.workoutId,
+        callbackUrl: event.fileUrl ?? null,
+        fileType: event.fileType ?? (event.eventType === EVENT_FILE ? "FIT" : null),
+        name: event.name ?? null,
+        startedAt: event.startedAt ?? null,
+        duration: event.duration ?? null,
+        distance: event.distance ?? null,
+      },
+      { reason: "garmin webhook notification" },
+    );
+  },
+};
+
+function safeHost(url: string): string {
+  try {
+    return new URL(url).host;
+  } catch {
+    return "<unparseable>";
+  }
+}
diff --git a/apps/journal/app/lib/connected-services/providers/index.ts b/apps/journal/app/lib/connected-services/providers/index.ts
index ff04735..ba54534 100644
--- a/apps/journal/app/lib/connected-services/providers/index.ts
+++ b/apps/journal/app/lib/connected-services/providers/index.ts
@@ -5,9 +5,11 @@
 import { registerManifest } from "../registry.ts";
 import { wahooManifest } from "./wahoo/manifest.ts";
 import { komootManifest } from "./komoot/manifest.ts";
+import { garminManifest } from "./garmin/manifest.ts";
 
 registerManifest(wahooManifest);
 registerManifest(komootManifest);
+registerManifest(garminManifest);
 
 // Re-export so callers (mostly tests) can grab a manifest directly.
-export { wahooManifest, komootManifest };
+export { wahooManifest, komootManifest, garminManifest };
diff --git a/apps/journal/app/lib/connected-services/providers/wahoo/webhook.test.ts b/apps/journal/app/lib/connected-services/providers/wahoo/webhook.test.ts
index 01d2acd..6d03966 100644
--- a/apps/journal/app/lib/connected-services/providers/wahoo/webhook.test.ts
+++ b/apps/journal/app/lib/connected-services/providers/wahoo/webhook.test.ts
@@ -1,6 +1,6 @@
 // Contract tests for the Wahoo WebhookReceiver capability adapter.
 //
-// Seam: parseWebhook(body) -> WebhookEvent | null
+// Seam: parseWebhook(body) -> WebhookEvent[] (empty = nothing actionable)
 //       handle(event) -> void  (creates an activity if file present, dedups via sync_imports)
 
 import { describe, it, expect, beforeEach, vi } from "vitest";
@@ -41,22 +41,24 @@ describe("wahooWebhook.parseWebhook", () => {
         file: { url: "https://cdn.example/42.fit" },
       },
     });
-    expect(event).toEqual({
-      eventType: "workout_summary",
-      providerUserId: "7",
-      workoutId: "42",
-      fileUrl: "https://cdn.example/42.fit",
-    });
+    expect(event).toEqual([
+      {
+        eventType: "workout_summary",
+        providerUserId: "7",
+        workoutId: "42",
+        fileUrl: "https://cdn.example/42.fit",
+      },
+    ]);
   });
 
-  it("returns null for unrecognized event types", () => {
-    expect(wahooWebhook.parseWebhook({ event_type: "other" })).toBeNull();
+  it("returns no events for unrecognized event types", () => {
+    expect(wahooWebhook.parseWebhook({ event_type: "other" })).toEqual([]);
   });
 
-  it("returns null when user.id is missing", () => {
+  it("returns no events when user.id is missing", () => {
     expect(
       wahooWebhook.parseWebhook({ event_type: "workout_summary", user: {} }),
-    ).toBeNull();
+    ).toEqual([]);
   });
 });
 
diff --git a/apps/journal/app/lib/connected-services/providers/wahoo/webhook.ts b/apps/journal/app/lib/connected-services/providers/wahoo/webhook.ts
index 6473b0b..8b77f58 100644
--- a/apps/journal/app/lib/connected-services/providers/wahoo/webhook.ts
+++ b/apps/journal/app/lib/connected-services/providers/wahoo/webhook.ts
@@ -23,18 +23,20 @@ interface WahooWebhookBody {
 
 
 export const wahooWebhook: WebhookReceiver = {
-  parseWebhook(body: unknown): WebhookEvent | null {
+  parseWebhook(body: unknown): WebhookEvent[] {
     const payload = body as WahooWebhookBody;
-    if (payload.event_type !== "workout_summary" || !payload.user?.id) return null;
+    if (payload.event_type !== "workout_summary" || !payload.user?.id) return [];
 
-    return {
-      eventType: payload.event_type,
-      providerUserId: String(payload.user.id),
-      workoutId: String(
-        payload.workout_summary?.workout?.id ?? payload.workout_summary?.id ?? "",
-      ),
-      fileUrl: payload.workout_summary?.file?.url,
-    };
+    return [
+      {
+        eventType: payload.event_type,
+        providerUserId: String(payload.user.id),
+        workoutId: String(
+          payload.workout_summary?.workout?.id ?? payload.workout_summary?.id ?? "",
+        ),
+        fileUrl: payload.workout_summary?.file?.url,
+      },
+    ];
   },
 
   async handle(event: WebhookEvent): Promise<void> {
diff --git a/apps/journal/app/lib/connected-services/registry.ts b/apps/journal/app/lib/connected-services/registry.ts
index 457a79b..3bac1c7 100644
--- a/apps/journal/app/lib/connected-services/registry.ts
+++ b/apps/journal/app/lib/connected-services/registry.ts
@@ -59,6 +59,15 @@ export interface WebhookEvent {
   providerUserId: string;
   workoutId: string;
   fileUrl?: string;
+  // Optional summary stats carried by providers whose notifications
+  // include them (Garmin pushes summaries; a FIT-less activity is still
+  // importable stats-only). Providers without summaries leave these out.
+  name?: string;
+  startedAt?: string;
+  duration?: number | null;
+  distance?: number | null;
+  // File format behind fileUrl when the provider says (FIT | GPX | TCX).
+  fileType?: string;
 }
 
 // CapabilityContext gives capability adapters the tools they need without
@@ -81,7 +90,10 @@ export interface RoutePusher {
 }
 
 export interface WebhookReceiver {
-  parseWebhook(body: unknown): WebhookEvent | null;
+  // One provider POST can carry many events (Garmin batches
+  // notifications). Single-event providers return a one-element array;
+  // an empty array means "nothing actionable" and the route 200s.
+  parseWebhook(body: unknown): WebhookEvent[];
   handle(event: WebhookEvent): Promise<void>;
 }
 
@@ -99,13 +111,30 @@ export interface ProviderManifest {
   // Custom connect page URL. When set, the connections settings page links
   // here instead of the default OAuth connect endpoint.
   connectUrl?: string;
+  // Custom import page URL. When set, the connections settings page links
+  // here instead of the generic /sync/import/<id> pick-list page (Garmin
+  // has no list endpoint — its import page is a backfill requester).
+  importUrl?: string;
+  // When defined and returning false, the provider is hidden from the
+  // connections settings page (e.g. instance has no API credentials for
+  // it). Undefined = always shown.
+  configured?: () => boolean;
+  // OAuth2 PKCE: when true, the connect route generates a code verifier
+  // (carried in an httpOnly cookie across the redirect) and passes the
+  // S256 challenge to buildAuthUrl / the verifier to exchangeCode.
+  pkce?: boolean;
   // OAuth authorization URL builder (for the connect flow).
-  buildAuthUrl?: (redirectUri: string, state: string) => string;
+  buildAuthUrl?: (
+    redirectUri: string,
+    state: string,
+    extras?: { codeChallenge?: string },
+  ) => string;
   // OAuth code exchange (for the callback). Returns the credential blob to
   // store and the granted scopes.
   exchangeCode?: (
     code: string,
     redirectUri: string,
+    extras?: { codeVerifier?: string },
   ) => Promise<{
     credentials: unknown;
     providerUserId: string | null;
diff --git a/apps/journal/app/lib/sync/imports.server.ts b/apps/journal/app/lib/sync/imports.server.ts
index 757a201..aa5f3cb 100644
--- a/apps/journal/app/lib/sync/imports.server.ts
+++ b/apps/journal/app/lib/sync/imports.server.ts
@@ -51,9 +51,23 @@ export async function importActivity(
   userId: string,
   provider: string,
   externalWorkoutId: string,
-  input: { name: string; gpx?: string },
+  input: {
+    name: string;
+    gpx?: string;
+    // Stats-only imports (no GPS file — e.g. Garmin notifications for
+    // FIT-less activities) carry whatever the provider's summary had.
+    distance?: number | null;
+    duration?: number | null;
+    startedAt?: Date | null;
+  },
 ): Promise<{ activityId: string }> {
-  const activityId = await createActivity(userId, { name: input.name, gpx: input.gpx });
+  const activityId = await createActivity(userId, {
+    name: input.name,
+    gpx: input.gpx,
+    distance: input.distance,
+    duration: input.duration,
+    startedAt: input.startedAt,
+  });
   await recordImport(userId, provider, externalWorkoutId, activityId);
   return { activityId };
 }
diff --git a/apps/journal/app/routes.ts b/apps/journal/app/routes.ts
index 77077c8..19c02e8 100644
--- a/apps/journal/app/routes.ts
+++ b/apps/journal/app/routes.ts
@@ -58,6 +58,7 @@ export default [
   route("api/settings/passkey/delete", "routes/api.settings.passkey.delete.ts"),
   route("api/settings/delete-account", "routes/api.settings.delete-account.ts"),
   route("sync/import/komoot", "routes/sync.import.komoot.tsx"),
+  route("sync/import/garmin", "routes/sync.import.garmin.tsx"),
   route("sync/import/:provider", "routes/sync.import.$provider.tsx"),
   route("api/sync/komoot/verify", "routes/api.sync.komoot.verify.ts"),
   route("api/sync/komoot/connect", "routes/api.sync.komoot.connect.ts"),
diff --git a/apps/journal/app/routes/api.sync.callback.$provider.ts b/apps/journal/app/routes/api.sync.callback.$provider.ts
index 800db0c..e9c0db0 100644
--- a/apps/journal/app/routes/api.sync.callback.$provider.ts
+++ b/apps/journal/app/routes/api.sync.callback.$provider.ts
@@ -5,6 +5,8 @@ import { requireSessionUser } from "~/lib/auth/session.server";
 import { getManifest, link } from "~/lib/connected-services";
 import {
   decodeOAuthState,
+  readPkceVerifier,
+  clearPkceCookieHeader,
 } from "~/lib/connected-services/oauth-state.server";
 import { pushRouteToProvider } from "~/lib/connected-services/push-action.server";
 
@@ -32,8 +34,18 @@ export async function loader({ params, request }: Route.LoaderArgs) {
   const origin = getOrigin();
   const redirectUri = `${origin}/api/sync/callback/${params.provider}`;
 
+  // PKCE providers: recover the verifier from the connect-time cookie.
+  const codeVerifier = manifest.pkce ? readPkceVerifier(request) : null;
+  if (manifest.pkce && !codeVerifier) {
+    return redirect(`${fallbackReturn}?error=sync_failed`);
+  }
+
   try {
-    const exchange = await manifest.exchangeCode(code, redirectUri);
+    const exchange = await manifest.exchangeCode(
+      code,
+      redirectUri,
+      codeVerifier ? { codeVerifier } : undefined,
+    );
     await link({
       userId: user.id,
       provider: manifest.id,
@@ -65,5 +77,9 @@ export async function loader({ params, request }: Route.LoaderArgs) {
     return redirect(`${target}?push=${outcome.status}`);
   }
 
-  return redirect(state.returnTo ?? "/settings");
+  return redirect(state.returnTo ?? "/settings", {
+    // Spent verifier — clear it regardless of which provider this was
+    // (harmless no-op for non-PKCE providers without the cookie).
+    headers: { "Set-Cookie": clearPkceCookieHeader() },
+  });
 }
diff --git a/apps/journal/app/routes/api.sync.connect.$provider.ts b/apps/journal/app/routes/api.sync.connect.$provider.ts
index cfbc2ca..6e27d09 100644
--- a/apps/journal/app/routes/api.sync.connect.$provider.ts
+++ b/apps/journal/app/routes/api.sync.connect.$provider.ts
@@ -3,7 +3,11 @@ import { getOrigin } from "~/lib/config.server";
 import type { Route } from "./+types/api.sync.connect.$provider";
 import { requireSessionUser } from "~/lib/auth/session.server";
 import { getManifest } from "~/lib/connected-services";
-import { encodeOAuthState } from "~/lib/connected-services/oauth-state.server";
+import {
+  encodeOAuthState,
+  generatePkcePair,
+  pkceCookieHeader,
+} from "~/lib/connected-services/oauth-state.server";
 
 export async function loader({ params, request }: Route.LoaderArgs) {
   await requireSessionUser(request);
@@ -17,5 +21,15 @@ export async function loader({ params, request }: Route.LoaderArgs) {
   const redirectUri = `${origin}/api/sync/callback/${params.provider}`;
   const state = encodeOAuthState({ returnTo: "/settings/connections" });
 
+  // PKCE providers (Garmin): the verifier crosses the redirect in an
+  // httpOnly cookie; only the S256 challenge goes to the provider.
+  if (manifest.pkce) {
+    const { verifier, challenge } = generatePkcePair();
+    return redirect(
+      manifest.buildAuthUrl(redirectUri, state, { codeChallenge: challenge }),
+      { headers: { "Set-Cookie": pkceCookieHeader(verifier) } },
+    );
+  }
+
   return redirect(manifest.buildAuthUrl(redirectUri, state));
 }
diff --git a/apps/journal/app/routes/api.sync.webhook.$provider.test.ts b/apps/journal/app/routes/api.sync.webhook.$provider.test.ts
index 7c57b2f..0ba4804 100644
--- a/apps/journal/app/routes/api.sync.webhook.$provider.test.ts
+++ b/apps/journal/app/routes/api.sync.webhook.$provider.test.ts
@@ -30,7 +30,7 @@ describe("POST /api/sync/webhook/:provider", () => {
   beforeEach(() => {
     parseWebhook.mockReset();
     handle.mockReset();
-    parseWebhook.mockReturnValue(null);
+    parseWebhook.mockReturnValue([]);
     vi.unstubAllEnvs();
   });
 
@@ -83,7 +83,7 @@ describe("POST /api/sync/webhook/:provider", () => {
   });
 
   it("invokes parseWebhook with a valid object body", async () => {
-    parseWebhook.mockReturnValue({ eventType: "x", providerUserId: "1", workoutId: "9" });
+    parseWebhook.mockReturnValue([{ eventType: "x", providerUserId: "1", workoutId: "9" }]);
     handle.mockResolvedValue(undefined);
     const res = await call({ event_type: "x" });
     expect(statusOf(res)).toBe(200);
diff --git a/apps/journal/app/routes/api.sync.webhook.$provider.ts b/apps/journal/app/routes/api.sync.webhook.$provider.ts
index 1cff459..a78c647 100644
--- a/apps/journal/app/routes/api.sync.webhook.$provider.ts
+++ b/apps/journal/app/routes/api.sync.webhook.$provider.ts
@@ -37,13 +37,13 @@ export async function action({ params, request }: Route.ActionArgs) {
     return data({ ok: true });
   }
 
-  const event = manifest.webhookReceiver.parseWebhook(body);
-  if (!event) return data({ ok: true });
-
-  try {
-    await manifest.webhookReceiver.handle(event);
-  } catch (e) {
-    console.error(`Webhook import failed for ${manifest.id}/${event.workoutId}:`, e);
+  const events = manifest.webhookReceiver.parseWebhook(body);
+  for (const event of events) {
+    try {
+      await manifest.webhookReceiver.handle(event);
+    } catch (e) {
+      console.error(`Webhook import failed for ${manifest.id}/${event.workoutId}:`, e);
+    }
   }
 
   return data({ ok: true });
diff --git a/apps/journal/app/routes/legal.privacy.tsx b/apps/journal/app/routes/legal.privacy.tsx
index 303f26c..21518be 100644
--- a/apps/journal/app/routes/legal.privacy.tsx
+++ b/apps/journal/app/routes/legal.privacy.tsx
@@ -309,6 +309,21 @@ export default function PrivacyPage() {
             importieren. Die Verbindung kann jederzeit in den Einstellungen
             getrennt werden.
           </li>
+          <li>
+            <strong>Garmin</strong> (Garmin Ltd.) – Optionaler Import von
+            Aktivitäten aus Garmin Connect. Beim Verbinden werden
+            OAuth-Tokens ausgetauscht und die Garmin-Nutzer-ID gespeichert.
+            Garmin übermittelt anschließend neue Aktivitäten (inkl.
+            GPS-Aufzeichnung als FIT-Datei) automatisch an diese Instanz;
+            ältere Aktivitäten nur auf Ihre ausdrückliche Anforderung
+            (Zeitraum-Import). Es werden keine Gesundheitsdaten (Schlaf,
+            Herzfrequenz-Tageswerte o.&nbsp;ä.) abgerufen — nur Aktivitäten.
+            Widerrufen Sie den Zugriff bei Garmin oder trennen Sie die
+            Verbindung in den Einstellungen, endet die Übermittlung sofort;
+            bereits importierte Aktivitäten bleiben in Ihrem Journal und
+            können dort gelöscht werden. Es gilt die Datenschutzerklärung
+            von Garmin.
+          </li>
           <li>
             <strong>Hosting</strong> – Die Dienste werden in Rechenzentren
             innerhalb der EU betrieben. Ein Auftragsverarbeitungsvertrag mit
@@ -327,7 +342,13 @@ export default function PrivacyPage() {
           Wahoo&rdquo; on a route — sent so the route appears on your
           ELEMNT/BOLT/ROAM); Komoot (only when you opt in: public mode
           stores your Komoot user ID only; authenticated mode stores your
-          encrypted Komoot password); hosting provider in the EU under a DPA.
+          encrypted Komoot password); Garmin (only when you opt in: OAuth
+          tokens and your Garmin user ID; Garmin then pushes new activities
+          including GPS files to this instance automatically, and older
+          activities only when you request a date range — activities only,
+          never health metrics; revoking at Garmin or disconnecting here
+          stops the flow immediately, imported activities stay yours);
+          hosting provider in the EU under a DPA.
         </p>
       </section>
 
diff --git a/apps/journal/app/routes/settings.connections.server.ts b/apps/journal/app/routes/settings.connections.server.ts
index 41b14f9..c89c3a0 100644
--- a/apps/journal/app/routes/settings.connections.server.ts
+++ b/apps/journal/app/routes/settings.connections.server.ts
@@ -21,16 +21,21 @@ export async function loadConnectionsSettings(request: Request) {
     .from(connectedServices)
     .where(eq(connectedServices.userId, user.id));
 
-  const providers = getAllManifests().map((m) => {
-    const conn = connections.find((c) => c.provider === m.id);
-    return {
-      id: m.id,
-      name: m.displayName,
-      connected: !!conn,
-      providerUserId: conn?.providerUserId,
-      connectUrl: m.connectUrl ?? null,
-    };
-  });
+  const providers = getAllManifests()
+    // Providers can hide themselves when the instance lacks their API
+    // credentials (Garmin: program keys are per-operator).
+    .filter((m) => m.configured?.() ?? true)
+    .map((m) => {
+      const conn = connections.find((c) => c.provider === m.id);
+      return {
+        id: m.id,
+        name: m.displayName,
+        connected: !!conn,
+        providerUserId: conn?.providerUserId,
+        connectUrl: m.connectUrl ?? null,
+        importUrl: m.importUrl ?? null,
+      };
+    });
 
   return { providers };
 }
diff --git a/apps/journal/app/routes/settings.connections.tsx b/apps/journal/app/routes/settings.connections.tsx
index 68ada37..9b255e3 100644
--- a/apps/journal/app/routes/settings.connections.tsx
+++ b/apps/journal/app/routes/settings.connections.tsx
@@ -52,7 +52,7 @@ export default function ConnectionsSettings({ loaderData }: Route.ComponentProps
             {p.connected ? (
               <div className="flex items-center gap-3">
                 <a
-                  href={`/sync/import/${p.id}`}
+                  href={p.importUrl ?? `/sync/import/${p.id}`}
                   className="text-sm text-blue-600 hover:underline"
                 >
                   {t("sync.import")}
diff --git a/apps/journal/app/routes/sync.import.garmin.server.ts b/apps/journal/app/routes/sync.import.garmin.server.ts
new file mode 100644
index 0000000..275a40f
--- /dev/null
+++ b/apps/journal/app/routes/sync.import.garmin.server.ts
@@ -0,0 +1,91 @@
+// Server logic for the Garmin import page (spec: garmin-import,
+// "Historical import via backfill"). Garmin has no list endpoint, so
+// this page is a date-range backfill requester with honest async
+// progress — not a pick list.
+
+import { and, desc, eq, gte, count } from "drizzle-orm";
+import { requireSessionUser } from "~/lib/auth/session.server";
+import { getDb } from "~/lib/db";
+import { importBatches, syncImports } from "@trails-cool/db/schema/journal";
+import { getService } from "~/lib/connected-services/manager";
+import { requestBackfill } from "~/lib/connected-services/providers/garmin/backfill";
+
+export interface GarminBackfillRow {
+  id: string;
+  rangeStart: string | null;
+  rangeEnd: string | null;
+  requestedAt: string;
+  // Garmin activities imported since this request was made. Activities
+  // arrive asynchronously and notifications don't carry a batch id, so
+  // "imports since the request" is the honest measurable proxy for
+  // range progress (overlapping ranges share arrivals).
+  importedSince: number;
+}
+
+export async function loadGarminImportPage(request: Request) {
+  const user = await requireSessionUser(request);
+  const service = await getService(user.id, "garmin");
+
+  if (!service) {
+    return { connected: false as const, status: null, batches: [] as GarminBackfillRow[] };
+  }
+
+  const db = getDb();
+  const rows = await db
+    .select()
+    .from(importBatches)
+    .where(and(eq(importBatches.userId, user.id), eq(importBatches.provider, "garmin")))
+    .orderBy(desc(importBatches.startedAt))
+    .limit(20);
+
+  const batches: GarminBackfillRow[] = [];
+  for (const row of rows) {
+    const [imported] = await db
+      .select({ n: count() })
+      .from(syncImports)
+      .where(
+        and(
+          eq(syncImports.userId, user.id),
+          eq(syncImports.provider, "garmin"),
+          gte(syncImports.importedAt, row.startedAt),
+        ),
+      );
+    batches.push({
+      id: row.id,
+      rangeStart: row.rangeStart?.toISOString() ?? null,
+      rangeEnd: row.rangeEnd?.toISOString() ?? null,
+      requestedAt: row.startedAt.toISOString(),
+      importedSince: imported?.n ?? 0,
+    });
+  }
+
+  return { connected: true as const, status: service.status, batches };
+}
+
+export type GarminBackfillActionResult =
+  | { ok: true; chunks: number }
+  | { ok: false; error: "not_connected" | "needs_relink" | "invalid_range" | "request_failed" };
+
+export async function handleGarminBackfillAction(
+  request: Request,
+): Promise<GarminBackfillActionResult> {
+  const user = await requireSessionUser(request);
+  const service = await getService(user.id, "garmin");
+  if (!service) return { ok: false, error: "not_connected" };
+  if (service.status !== "active") return { ok: false, error: "needs_relink" };
+
+  const form = await request.formData();
+  const from = new Date(String(form.get("from") ?? ""));
+  const to = new Date(String(form.get("to") ?? ""));
+  if (isNaN(from.getTime()) || isNaN(to.getTime()) || from >= to || to > new Date()) {
+    return { ok: false, error: "invalid_range" };
+  }
+
+  try {
+    const { chunks } = await requestBackfill({ id: service.id, userId: user.id }, from, to);
+    return { ok: true, chunks };
+  } catch (e) {
+    console.error("garmin backfill request failed:", e);
+    return { ok: false, error: "request_failed" };
+  }
+}
diff --git a/apps/journal/app/routes/sync.import.garmin.tsx b/apps/journal/app/routes/sync.import.garmin.tsx
new file mode 100644
index 0000000..7642647
--- /dev/null
+++ b/apps/journal/app/routes/sync.import.garmin.tsx
@@ -0,0 +1,112 @@
+import { data, Form, Link, useNavigation } from "react-router";
+import { useTranslation } from "react-i18next";
+import type { Route } from "./+types/sync.import.garmin";
+import { ClientDate } from "~/components/ClientDate";
+
+export function meta() {
+  return [{ title: "Garmin import — trails.cool" }];
+}
+
+export async function loader({ request }: Route.LoaderArgs) {
+  const { loadGarminImportPage } = await import("./sync.import.garmin.server");
+  return data(await loadGarminImportPage(request));
+}
+
+export async function action({ request }: Route.ActionArgs) {
+  const { handleGarminBackfillAction } = await import("./sync.import.garmin.server");
+  return data(await handleGarminBackfillAction(request));
+}
+
+export default function GarminImport({ loaderData, actionData }: Route.ComponentProps) {
+  const { t } = useTranslation(["journal"]);
+  const navigation = useNavigation();
+  const busy = navigation.state !== "idle";
+
+  if (!loaderData.connected) {
+    return (
+      <div className="mx-auto max-w-2xl px-4 py-8">
+        <h1 className="text-2xl font-bold text-gray-900">{t("sync.garmin.title")}</h1>
+        <p className="mt-4 text-sm text-gray-600">{t("sync.garmin.notConnected")}</p>
+        <Link to="/settings/connections" className="mt-2 inline-block text-sm text-blue-600 hover:underline">
+          {t("sync.garmin.goConnect")}
+        </Link>
+      </div>
+    );
+  }
+
+  return (
+    <div className="mx-auto max-w-2xl px-4 py-8">
+      <h1 className="text-2xl font-bold text-gray-900">{t("sync.garmin.title")}</h1>
+      <p className="mt-2 text-sm text-gray-600">{t("sync.garmin.subtitle")}</p>
+
+      {loaderData.status !== "active" && (
+        <div role="alert" className="mt-4 rounded-md border border-amber-200 bg-amber-50 px-4 py-3 text-sm text-amber-900">
+          {t("sync.garmin.needsRelink")}
+        </div>
+      )}
+
+      <Form method="post" className="mt-6 flex flex-wrap items-end gap-3">
+        <label className="block text-sm">
+          <span className="text-gray-700">{t("sync.garmin.from")}</span>
+          <input
+            type="date"
+            name="from"
+            required
+            className="mt-1 block rounded-md border border-gray-300 px-3 py-2 text-sm"
+          />
+        </label>
+        <label className="block text-sm">
+          <span className="text-gray-700">{t("sync.garmin.to")}</span>
+          <input
+            type="date"
+            name="to"
+            required
+            className="mt-1 block rounded-md border border-gray-300 px-3 py-2 text-sm"
+          />
+        </label>
+        <button
+          type="submit"
+          disabled={busy || loaderData.status !== "active"}
+          className="rounded-md bg-blue-600 px-4 py-2 text-sm text-white hover:bg-blue-700 disabled:opacity-50"
+        >
+          {busy ? t("sync.garmin.requesting") : t("sync.garmin.request")}
+        </button>
+      </Form>
+
+      {actionData && "ok" in actionData && actionData.ok && (
+        <p className="mt-3 text-sm text-green-700">{t("sync.garmin.requested")}</p>
+      )}
+      {actionData && "ok" in actionData && !actionData.ok && (
+        <p role="alert" className="mt-3 text-sm text-red-700">
+          {t(`sync.garmin.errors.${actionData.error}`)}
+        </p>
+      )}
+
+      <p className="mt-6 text-xs text-gray-500">{t("sync.garmin.asyncNote")}</p>
+
+      {loaderData.batches.length > 0 && (
+        <ul className="mt-4 space-y-2">
+          {loaderData.batches.map((b) => (
+            <li
+              key={b.id}
+              className="flex items-center justify-between rounded-md border border-gray-200 px-4 py-3 text-sm"
+            >
+              <span className="text-gray-900">
+                {b.rangeStart && b.rangeEnd ? (
+                  <>
+                    <ClientDate iso={b.rangeStart} /> – <ClientDate iso={b.rangeEnd} />
+                  </>
+                ) : (
+                  <ClientDate iso={b.requestedAt} />
+                )}
+              </span>
+              <span className="text-gray-500">
+                {t("sync.garmin.importedSince", { count: b.importedSince })}
+              </span>
+            </li>
+          ))}
+        </ul>
+      )}
+    </div>
+  );
+}
diff --git a/apps/journal/server.ts b/apps/journal/server.ts
index 93342ac..682d93f 100644
--- a/apps/journal/server.ts
+++ b/apps/journal/server.ts
@@ -177,7 +177,8 @@ server.listen(port, async () => {
   const { importBatchesSweepJob } = await import("./app/jobs/import-batches-sweep.ts");
   const { sendWelcomeEmailJob } = await import("./app/jobs/send-welcome-email.ts");
   const { consumedJtiSweepJob } = await import("./app/jobs/consumed-jti-sweep.ts");
-  jobs.push(notificationsFanoutJob, notificationsPurgeJob, komootBulkImportJob, importBatchesSweepJob, sendWelcomeEmailJob, consumedJtiSweepJob);
+  const { garminImportActivityJob } = await import("./app/jobs/garmin-import-activity.ts");
+  jobs.push(notificationsFanoutJob, notificationsPurgeJob, komootBulkImportJob, importBatchesSweepJob, sendWelcomeEmailJob, consumedJtiSweepJob, garminImportActivityJob);
   // Federation jobs — registered only when federation is on.
   if (process.env.FEDERATION_ENABLED === "true") {
     const { backfillUserKeypairsJob } = await import("./app/jobs/backfill-user-keypairs.ts");
diff --git a/infrastructure/docker-compose.staging.yml b/infrastructure/docker-compose.staging.yml
index 1a09695..4e53d26 100644
--- a/infrastructure/docker-compose.staging.yml
+++ b/infrastructure/docker-compose.staging.yml
@@ -60,6 +60,8 @@ services:
       WAHOO_CLIENT_ID: ""
       WAHOO_CLIENT_SECRET: ""
       WAHOO_WEBHOOK_TOKEN: ""
+      GARMIN_CLIENT_ID: ${GARMIN_CLIENT_ID:-}
+      GARMIN_CLIENT_SECRET: ${GARMIN_CLIENT_SECRET:-}
       DEMO_BOT_ENABLED: ""
       # Federation (social-federation rollout). Enabled by cd-staging.yml
       # for persistent staging (12.2) and for PR previews (12.4 — every
diff --git a/infrastructure/docker-compose.yml b/infrastructure/docker-compose.yml
index dd2403b..1a7c623 100644
--- a/infrastructure/docker-compose.yml
+++ b/infrastructure/docker-compose.yml
@@ -53,6 +53,10 @@ services:
       WAHOO_CLIENT_ID: ${WAHOO_CLIENT_ID:-}
       WAHOO_CLIENT_SECRET: ${WAHOO_CLIENT_SECRET:-}
       WAHOO_WEBHOOK_TOKEN: ${WAHOO_WEBHOOK_TOKEN:-}
+      # Garmin Connect Developer Program keys (spec: garmin-import).
+      # Empty = the Garmin provider is hidden on /settings/connections.
+      GARMIN_CLIENT_ID: ${GARMIN_CLIENT_ID:-}
+      GARMIN_CLIENT_SECRET: ${GARMIN_CLIENT_SECRET:-}
       # Federation (ActivityPub, social-federation rollout 12.5). Empty
       # = off: every federation surface 404s — the safe self-host
       # default. The flagship turns it on via cd-apps.yml (same pattern
diff --git a/openspec/changes/garmin-import/design.md b/openspec/changes/garmin-import/design.md
index 79bc84a..a6eb181 100644
--- a/openspec/changes/garmin-import/design.md
+++ b/openspec/changes/garmin-import/design.md
@@ -28,7 +28,7 @@ Garmin specifics that shape everything below (Garmin Connect Developer Program,
 
 ### Decision: OAuth2 + PKCE rides the existing `oauth` credential kind
 
-Garmin's token blob is shape-compatible with `OAuthCredentials` (`access_token`, `refresh_token`, `expires_at`), so `credential_kind = 'oauth'` and the existing OAuth `CredentialAdapter` handle storage and refresh. PKCE only affects the **authorize/exchange** steps, which are already per-provider in the manifest's OAuth config — the manifest gains a code-verifier generation + `code_challenge` parameter, with the verifier carried through the OAuth `state` storage (`oauth-state.server.ts`) the same way the existing flow carries its state nonce.
+Garmin's token blob is shape-compatible with `OAuthCredentials` (`access_token`, `refresh_token`, `expires_at`), so `credential_kind = 'oauth'` and the existing OAuth `CredentialAdapter` handle storage and refresh. PKCE only affects the **authorize/exchange** steps, which are already per-provider in the manifest's OAuth config — the manifest gains a code-verifier generation + `code_challenge` parameter. *Corrected during apply:* the existing `state` param is intent-encoding reflected through redirects (visible in URLs), not server-side storage — and the verifier must never appear in a URL. It rides a short-lived httpOnly cookie scoped to the callback path instead (`oauth-state.server.ts` PKCE helpers; manifests opt in via `pkce: true`).
 
 **Alternative considered:** a new `oauth-pkce` credential kind. Rejected — the *stored* credential is identical; PKCE is a handshake detail, not a credential shape. A new kind would fork the adapter for zero storage benefit.
 
diff --git a/openspec/changes/garmin-import/tasks.md b/openspec/changes/garmin-import/tasks.md
index ba042f4..77cabf3 100644
--- a/openspec/changes/garmin-import/tasks.md
+++ b/openspec/changes/garmin-import/tasks.md
@@ -2,37 +2,40 @@
 
 ## 1. Provider scaffold + OAuth
 
-- [ ] 1.1 Create `providers/garmin/manifest.ts`: `credential_kind = 'oauth'`, Garmin OAuth2 endpoints, scopes, env-gated `GARMIN_CLIENT_ID`/`GARMIN_CLIENT_SECRET`; register via `providers/index.ts`
-- [ ] 1.2 PKCE support in the Garmin authorize/exchange flow: generate code verifier, carry it through `oauth-state.server.ts` alongside the state nonce, send `code_challenge`/`code_verifier` on authorize/exchange (token *storage and refresh* stay on the existing oauth `CredentialAdapter`)
-- [ ] 1.3 Capture the Garmin user id at connect time and store as `provider_user_id`
-- [ ] 1.4 `/settings/connections` shows Garmin connect/disconnect; row hidden/disabled when env vars are absent (mirror Wahoo's gating); i18n strings (en + de)
-- [ ] 1.5 Unit tests: manifest registration, PKCE parameter generation/verification, connect flow state round-trip
+- [x] 1.1 Create `providers/garmin/manifest.ts`: `credential_kind = 'oauth'`, Garmin OAuth2 endpoints, scopes, env-gated `GARMIN_CLIENT_ID`/`GARMIN_CLIENT_SECRET`; register via `providers/index.ts`
+- [x] 1.2 PKCE support in the Garmin authorize/exchange flow: generate code verifier, carry it through `oauth-state.server.ts` alongside the state nonce, send `code_challenge`/`code_verifier` on authorize/exchange (token *storage and refresh* stay on the existing oauth `CredentialAdapter`)
+  > Design correction during apply: the `state` param is intent-encoding only (visible in redirects), not server-side storage — the verifier must never appear in a URL, so it rides a short-lived httpOnly cookie scoped to `/api/sync/callback` instead. Manifests opt in via `pkce: true`.
+- [x] 1.3 Capture the Garmin user id at connect time and store as `provider_user_id`
+- [x] 1.4 `/settings/connections` shows Garmin connect/disconnect; row hidden/disabled when env vars are absent (mirror Wahoo's gating); i18n strings (en + de)
+- [x] 1.5 Unit tests: manifest registration, PKCE parameter generation/verification, connect flow state round-trip
 
 ## 2. Webhook ingestion
 
-- [ ] 2.1 `WebhookReceiver` adapter for `/api/sync/webhook/garmin`: accept POST, normalize ping (fetch callback URL) and push (inline payload) into one internal activity-notification shape, respond 200 fast
-- [ ] 2.2 Callback-URL host allowlist (Garmin API hosts only) — drop + log anything else; never fetch unvalidated URLs (SSRF guard)
-- [ ] 2.3 pg-boss job `garmin-import-activity`: resolve user via `provider_user_id`, fetch FIT via `withFreshCredentials`, convert via shared `fit.ts`, create activity (GPX + stats + geometry; stats-only when no FIT), record `sync_imports`; idempotent on duplicate notifications; respect 429/Retry-After in retry policy
-- [ ] 2.4 Unknown-user notifications → 200, no processing; unknown notification types → log + 200
-- [ ] 2.5 Tests with recorded notification + FIT fixtures: ping path, push path, dedupe, unknown user, SSRF rejection, FIT-less stats-only
+- [x] 2.1 `WebhookReceiver` adapter for `/api/sync/webhook/garmin`: accept POST, normalize ping (fetch callback URL) and push (inline payload) into one internal activity-notification shape, respond 200 fast
+- [x] 2.2 Callback-URL host allowlist (Garmin API hosts only) — drop + log anything else; never fetch unvalidated URLs (SSRF guard)
+- [x] 2.3 pg-boss job `garmin-import-activity`: resolve user via `provider_user_id`, fetch FIT via `withFreshCredentials`, convert via shared `fit.ts`, create activity (GPX + stats + geometry; stats-only when no FIT), record `sync_imports`; idempotent on duplicate notifications; respect 429/Retry-After in retry policy
+- [x] 2.4 Unknown-user notifications → 200, no processing; unknown notification types → log + 200
+- [x] 2.5 Tests with recorded notification + FIT fixtures: ping path, push path, dedupe, unknown user, SSRF rejection, FIT-less stats-only
+  > Fixtures are doc-shaped (no live credentials yet — rollout 6.x); real recorded payloads replace them during the staging soak if shapes differ. The generic webhook route + Wahoo receiver moved to an array event contract (`parseWebhook(): WebhookEvent[]`) since Garmin batches notifications.
 
 ## 3. Backfill (historical import)
 
-- [ ] 3.1 Backfill request client: chunk a user-supplied date range into Garmin's per-request window; issue requests via `withFreshCredentials`
-- [ ] 3.2 Import page `/settings/connections/garmin/import`: date-range form, list of requested ranges, count of imported activities per range, honest async messaging; i18n (en + de)
-- [ ] 3.3 Persist backfill requests (range, requested_at, user) so progress survives reloads — smallest storage that works (reuse existing tables if possible; new table only if not)
-- [ ] 3.4 Tests: chunking math, overlap re-request safety (dedupe via `sync_imports`), progress counting
+- [x] 3.1 Backfill request client: chunk a user-supplied date range into Garmin's per-request window; issue requests via `withFreshCredentials`
+- [x] 3.2 Import page `/settings/connections/garmin/import`: date-range form, list of requested ranges, count of imported activities per range, honest async messaging; i18n (en + de)
+- [x] 3.3 Persist backfill requests (range, requested_at, user) so progress survives reloads — smallest storage that works (reuse existing tables if possible; new table only if not)
+  > Reused `import_batches` with two new nullable columns (`range_start`, `range_end`) — a smaller footprint than a new table, and provider-agnostic for future ranged backfills. (Deviates from the proposal's "Schema: none"; additive only.) Progress counts sync_imports rows since the request — notifications carry no batch id, so per-range attribution is a proxy by design.
+- [x] 3.4 Tests: chunking math, overlap re-request safety (dedupe via `sync_imports`), progress counting
 
 ## 4. Deregistration + lifecycle
 
-- [ ] 4.1 Handle Garmin deregistration notifications: set `connected_services.status = 'revoked'`, short-circuit subsequent Garmin calls, surface the standard re-connect prompt
-- [ ] 4.2 Tests: deregistration flips status; revoked connection blocks backfill/import paths
+- [x] 4.1 Handle Garmin deregistration notifications: set `connected_services.status = 'revoked'`, short-circuit subsequent Garmin calls, surface the standard re-connect prompt
+- [x] 4.2 Tests: deregistration flips status; revoked connection blocks backfill/import paths
 
 ## 5. Provenance + docs
 
-- [ ] 5.1 "Imported from garmin" badge works via the existing provenance path; delete-and-reimport clears `sync_imports`
-- [ ] 5.2 Privacy manifest entry on `/legal/privacy` (en legal-manifest + de legal section): what we pull from Garmin, what Garmin learns, deletion/revocation semantics
-- [ ] 5.3 Secrets wiring: `GARMIN_CLIENT_ID`/`GARMIN_CLIENT_SECRET` in SOPS `secrets.app.env`, compose env (prod + staging), `.env.example` notes
+- [x] 5.1 "Imported from garmin" badge works via the existing provenance path; delete-and-reimport clears `sync_imports`
+- [x] 5.2 Privacy manifest entry on `/legal/privacy` (en legal-manifest + de legal section): what we pull from Garmin, what Garmin learns, deletion/revocation semantics
+- [x] 5.3 Secrets wiring: `GARMIN_CLIENT_ID`/`GARMIN_CLIENT_SECRET` in SOPS `secrets.app.env`, compose env (prod + staging), `.env.example` notes
 
 ## 6. Rollout (gated on Garmin developer program approval)
 
diff --git a/packages/db/src/schema/journal.ts b/packages/db/src/schema/journal.ts
index 7bf9bce..7167368 100644
--- a/packages/db/src/schema/journal.ts
+++ b/packages/db/src/schema/journal.ts
@@ -340,6 +340,11 @@ export const importBatches = journalSchema.table("import_batches", {
   importedCount: integer("imported_count").notNull().default(0),
   duplicateCount: integer("duplicate_count").notNull().default(0),
   errorMessage: text("error_message"),
+  // Ranged backfill requests (Garmin): the activity time window this
+  // batch asked the provider to re-deliver. NULL for pick-list style
+  // imports (komoot bulk) that aren't range-shaped.
+  rangeStart: timestamp("range_start", { withTimezone: true }),
+  rangeEnd: timestamp("range_end", { withTimezone: true }),
   startedAt: timestamp("started_at", { withTimezone: true }).notNull().defaultNow(),
   completedAt: timestamp("completed_at", { withTimezone: true }),
 });
diff --git a/packages/i18n/src/locales/de.ts b/packages/i18n/src/locales/de.ts
index a1c8d84..8c9255c 100644
--- a/packages/i18n/src/locales/de.ts
+++ b/packages/i18n/src/locales/de.ts
@@ -478,6 +478,29 @@ export default {
       },
     },
     sync: {
+      garmin: {
+        title: "Von Garmin importieren",
+        subtitle:
+          "Garmin liefert Aktivitäten automatisch an trails.cool, sobald sie entstehen. Für ältere Aktivitäten fordere unten einen Zeitraum an — Garmin liefert sie asynchron nach.",
+        notConnected: "Dein Garmin-Konto ist noch nicht verbunden.",
+        goConnect: "Garmin in den Einstellungen verbinden",
+        needsRelink: "Deine Garmin-Verbindung muss neu verknüpft werden, bevor du Importe anfordern kannst.",
+        from: "Von",
+        to: "Bis",
+        request: "Import anfordern",
+        requesting: "Wird angefordert…",
+        requested: "Angefordert! Aktivitäten erscheinen, sobald Garmin sie liefert.",
+        asyncNote:
+          "Garmin verarbeitet Verlaufs-Anfragen auf ihrer Seite — große Zeiträume können dauern. Überlappende Zeiträume erneut anzufordern ist unproblematisch; nichts wird doppelt importiert.",
+        importedSince_one: "{{count}} Aktivität seit dieser Anfrage importiert",
+        importedSince_other: "{{count}} Aktivitäten seit dieser Anfrage importiert",
+        errors: {
+          not_connected: "Dein Garmin-Konto ist nicht verbunden.",
+          needs_relink: "Deine Garmin-Verbindung muss zuerst neu verknüpft werden.",
+          invalid_range: "Wähle einen gültigen Zeitraum in der Vergangenheit (Start vor Ende).",
+          request_failed: "Garmin hat die Anfrage abgelehnt — versuche es in ein paar Minuten erneut.",
+        },
+      },
       import: "Importieren",
       importFrom: "Import von {{provider}}",
       imported: "Importiert",
diff --git a/packages/i18n/src/locales/en.ts b/packages/i18n/src/locales/en.ts
index f6ee07f..72f4d6e 100644
--- a/packages/i18n/src/locales/en.ts
+++ b/packages/i18n/src/locales/en.ts
@@ -478,6 +478,29 @@ export default {
       },
     },
     sync: {
+      garmin: {
+        title: "Import from Garmin",
+        subtitle:
+          "Garmin delivers activities to trails.cool as they happen. To pull in your history, request a date range below — Garmin sends those activities over asynchronously.",
+        notConnected: "Your Garmin account isn't connected yet.",
+        goConnect: "Connect Garmin in settings",
+        needsRelink: "Your Garmin connection needs to be re-linked before requesting imports.",
+        from: "From",
+        to: "To",
+        request: "Request import",
+        requesting: "Requesting…",
+        requested: "Requested! Activities will appear as Garmin delivers them.",
+        asyncNote:
+          "Garmin processes history requests on their side — large ranges can take a while to arrive. Re-requesting an overlapping range is safe; nothing gets imported twice.",
+        importedSince_one: "{{count}} activity imported since this request",
+        importedSince_other: "{{count}} activities imported since this request",
+        errors: {
+          not_connected: "Your Garmin account isn't connected.",
+          needs_relink: "Your Garmin connection needs to be re-linked first.",
+          invalid_range: "Pick a valid date range in the past (start before end).",
+          request_failed: "Garmin rejected the request — try again in a few minutes.",
+        },
+      },
       import: "Import",
       importFrom: "Import from {{provider}}",
       imported: "Imported",