Flasher

A spaced-repetition flashcard app. Rust backend (axum + SQLite), Leptos/wasm frontend, passkey authentication. Runs as a single binary behind a reverse proxy; live at https://flasher.carstenfuehrmann.org.

Getting started

Prerequisites: a Rust toolchain with the wasm32-unknown-unknown target, plus trunk and wasm-bindgen-cli (cargo install trunk wasm-bindgen-cli).

just server     # builds the frontend, serves everything on http://localhost:3000

Development runs in an auth-free single-user bypass (FLASHER_USER, default dev); passkey auth activates when that variable is unset. Useful commands: just gate (full quality gate), just e2e (browser tests), just lighthouse, just mutants <crate>. Deployment: deploy/DEPLOY.md; updates on the server are sudo /opt/flasher/update.sh.

History & approach

This started as a .NET + Vite/React app and was ported to Rust by an AI agent (Kimi Code), with the owner acting as architect and reviewer. The port went well beyond a translation: passkey authentication (WebAuthn) replacing passwords, SQLite with embedded migrations replacing JSON files, markdown + KaTeX card rendering, URL routing with full state restore across reloads, and a one-command, AI-free deployment.

QA techniques used throughout: browser end-to-end tests driving real Chromium (including passkey ceremonies via a CDP virtual authenticator), snapshot testing, repeated unprimed adversarial reviews, mutation testing (cargo-mutants; the codebase is currently mutation-clean), and per-page Lighthouse checks. AGENTS.md documents the doctrine and workflow.

For developers / contributors

Migration policy. SQLite migrations are embedded and run on startup. The current schema is the squashed 0005 baseline; future changes are roll-forward migrations only. Before upgrading, back up flasher.db (the store also keeps automatic pre-migration copies in backups/); there is no downgrade path.

Read AGENTS.md first — it defines the testing doctrine (browser e2e as the only public test surface), the gates, and the review protocol. docs/plan.html is the living plan; docs/spec.md the original spec.

Layout: crates/ (backend workspace: types, core, store, auth, server, e2e, migrate), frontends/leptos/ (detached Leptos workspace), deploy/ (systemd, Caddy, update script), docs/.

License

MIT (see LICENSE).