Vinterliste

A small end-to-end-encrypted app for collecting winter activities — things to do when winter feels long. Activities can be:

• private — encrypted client-side; the server only ever sees ciphertext;
• semi-public — visible to everyone, but the creator is not shown;
• public — visible to everyone, attributed to the creator.

See SECURITY.md for the cryptographic model. It's load-bearing — read it before changing anything in shared/crypto.ts or the auth flow.

Stack

• Runtime: Bun 1.3+. TypeScript everywhere.
• HTTP: Hono on Bun.
• DB: bun:sqlite (built-in), WAL mode.
• Server password hashing: Bun.password (argon2id) — auth verifier only.
• Client crypto: libsodium-wrappers-sumo (WASM — the SUMO build is needed because the standard libsodium-wrappers doesn't ship crypto_pwhash). Argon2id via crypto_pwhash; AEAD via XChaCha20-Poly1305-IETF.
• Frontend: Svelte 5 + Vite. Private tag index in IndexedDB.
• Container: single oven/bun image, one volume for the SQLite file.

Layout

shared/      pure modules used by both server and frontend
  crypto.ts  libsodium-backed key derivation, AEAD, wrap/unwrap, helpers
  types.ts   wire-level types shared across the network boundary

server/      Bun + Hono backend
  db.ts            bun:sqlite, WAL, idempotent schema migration
  session.ts       opaque, server-stored sessions (httpOnly cookie)
  auth.ts          signup, challenge, login, logout, password change, recovery
  activities.ts    CRUD with visibility rules
  tags.ts          server-side (public/semi) tag store + autocomplete
  index.ts         Hono app + static frontend in production

frontend/    Vite + Svelte 5 SPA
  src/lib/crypto.ts      re-exports shared/crypto for bundling
  src/lib/api.ts         fetch wrapper for the JSON API
  src/lib/auth.ts        signup/login/recovery orchestration
  src/lib/tagIndex.ts    IndexedDB store for private tags
  src/lib/session.svelte.ts  in-memory DEK + current user
  src/components/        Svelte 5 components (Login, Signup, Recovery, Home, …)

tests/       Bun tests
  crypto.test.ts   round-trip wrap/unwrap, AEAD, password change, recovery

Containerfile  single-image build for podman

Running locally

You need Bun 1.3+ installed.

bun install

# 1. In one terminal — start the API on http://localhost:3000
bun run dev:server

# 2. In another terminal — start the Vite dev server on http://localhost:5173
#    (it proxies /api to :3000)
bun run dev:frontend

The dev server writes the SQLite file to data/vinterliste.db. Set VINTERLISTE_DB=/some/other/path to override.

Tests

bun test

The crypto tests cover:

• DEK wrap/unwrap via both the password and recovery paths;
• AEAD encrypt/decrypt round-trip, plus tamper and wrong-key rejection;
• password change preserves activity ciphertexts (DEK is the same);
• recovery unlocks even after multiple password changes;
• recovery-code normalisation handles dashes and casing;
• the safe alphabet excludes visually ambiguous characters.

Typecheck

bun run typecheck

Production build

bun run build:frontend    # produces frontend/dist
NODE_ENV=production bun run start

The server serves the SPA from frontend/dist in production. All non-/api/*, non-/assets/* requests fall through to index.html so client-side routing still works.

Container (podman)

The provided Containerfile builds a single image that serves API + frontend and persists the SQLite database in /app/data (one volume).

BUILDAH_FORMAT=docker podman build \
  --build-arg BUILD_DATE="$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
  --build-arg GIT_REVISION="$(git describe --always --dirty 2>/dev/null || echo dev)" \
  -t vinterliste:latest .

# Create a named volume for the SQLite file
podman volume create vinterliste-data

podman run --replace --name vinterliste \
  -p 3000:3000 \
  -v vinterliste-data:/app/data:Z \
  vinterliste:latest

# Visit http://localhost:3000

The container exposes /api/health for healthchecks and bakes the build date / git revision into both OCI labels and /etc/build-info.

Installable (PWA) + mobile

The SPA ships with a web app manifest (/manifest.webmanifest), an SVG icon (/icon.svg), and a small service worker (/sw.js) that caches the bundled shell for offline reads. The API itself is never cached — sessions and ciphertexts must come fresh from the server. On supported browsers (Chrome/Edge on Android and desktop, Firefox with the flag) you'll see an "Install" prompt; on iOS you can Add to Home Screen but iOS doesn't render SVG icons, so the home-screen icon will fall back to the page screenshot.

Layout adapts to small screens via:

• viewport set to width=device-width, initial-scale=1, viewport-fit=cover
• safe-area insets in padding so content doesn't slip under iOS notches
• min-height: 44px on buttons (WCAG 2.5.5 enhanced touch target)
• font-size: 16px on inputs below 480px so iOS doesn't auto-zoom

Promoting a moderator

Moderators can delete any semi or public activity (not private — those aren't visible to anyone else anyway). There's no admin UI; promotion is a one-liner against the SQLite file:

sqlite3 data/vinterliste.db \
  "UPDATE users SET is_moderator = 1 WHERE email = 'olemd@example.org';"

The user has to log out and back in for MeResponse.is_moderator to refresh.

Manual verification

After signing up an account, the spec asks you to inspect a private row directly in the DB and confirm only ciphertext is stored:

sqlite3 data/vinterliste.db \
  "SELECT id, visibility, title, loc_label, scheduled_at,
          length(ciphertext) AS ct_len, length(nonce) AS nc_len
   FROM activities WHERE visibility = 'private';"

You should see title, loc_label, and scheduled_at all NULL, and the ciphertext / nonce columns populated.

Status / scope

This is the scaffold from winter-list-claude-code-prompt.md. In scope:

• repo structure, schema, single-image container
• crypto module + tests
• signup / login / password change / recovery
• activity CRUD with strict visibility handling
• tag autocomplete (server tags table + client IndexedDB)

Explicitly out of scope for now:

• sharing/permissions beyond the three visibility levels
• comments, notifications, other social features
• native/mobile apps
• server-side full-text search over private data
• rate limiting on auth/recovery endpoints (defense-in-depth — the recovery verifier already closes the lockout-DoS hole; rate limiting reduces online brute-force surface)