trails/openspec/changes/transactional-emails/design.md
Ullrich Schäfer c7c1c275df
Add 8 proposed changes and old trails analysis
Proposed changes (all with proposal, design, specs, tasks):
- app-navigation (9 tasks) — nav bars for both apps
- planner-landing-page (7 tasks) — standalone landing page
- planner-multiplayer-awareness (13 tasks) — participants, cursors, names
- changelog (13 tasks) — public changelog with "what's new"
- transactional-emails (15 tasks) — magic link + welcome emails
- planner-features (18 tasks) — no-go areas, notes, recovery, rate limits
- komoot-import (23 tasks) — Komoot tour import
- route-features (37 tasks) — sharing, multi-day, spatial, photos

Also adds docs/old-trails-analysis.md with feature analysis from the
older trails project.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-25 03:57:20 +01:00

2.3 KiB

Context

The Journal has passkey auth (primary) and magic link login (fallback). Magic links work in dev (auto-redirect) but in production the link is only logged to console — users never receive it. No email infrastructure exists.

Goals / Non-Goals

Goals:

  • Actually deliver magic link emails in production
  • Send a welcome email after registration
  • Provider-agnostic email interface (easy to swap providers)
  • HTML templates with plain-text fallback
  • Easy to add new email types in the future (just add a template + call)
  • Dev mode: still log to console / return devLink (no real emails)

Non-Goals:

  • Marketing emails or newsletters
  • Email preferences / unsubscribe (only transactional)
  • Inline CSS / complex email layouts (keep it simple text-focused)
  • Queuing or retry logic (provider handles delivery)

Decisions

D1: Resend as email provider

Use Resend — simple API, generous free tier (3k emails/month), good developer experience. Single dependency: resend npm package.

Alternative considered: Nodemailer + SMTP. More complex setup, requires SMTP server. Resend is simpler for a small project.

Alternative considered: Postmark. Similar to Resend but less ergonomic API.

D2: Email module in apps/journal/app/lib/email.server.ts

Not a shared package — only the Journal sends emails. Keep it simple:

  • sendEmail(to, subject, html, text) — low-level sender
  • sendMagicLink(email, link) — template wrapper
  • sendWelcome(email, username) — template wrapper

In dev mode, sendEmail logs to console instead of calling Resend.

D3: Inline HTML templates

Simple functions returning HTML strings. No template engine. Each email type is a function: magicLinkTemplate(link), welcomeTemplate(username). Plain text generated by stripping tags.

D4: Sender domain: noreply@trails.cool

Requires DNS verification (DKIM/SPF records) with Resend. Add TXT records via Terraform or manually in Hetzner DNS.

Risks / Trade-offs

  • Resend vendor lock-in → Low risk. The sendEmail wrapper abstracts it. Swapping to nodemailer later is a one-file change.
  • DNS verification required → Must add DKIM/SPF records before emails work. Can use Resend's test domain initially.
  • Free tier limits → 3k/month is plenty for <100 users.