Bikefit

Open the app: https://libreble.github.io/bikefit/ — installable, works offline. Needs Chrome on Android or Chrome/Edge on desktop (Web Bluetooth). No account, no cloud.

Part of libreble — your devices, set free.

Offline, account-less BLE fitness logger + live workout dashboard. Target device: ICG IC-6. Local-first: no accounts, no cloud, no network calls at runtime — everything lives in the browser (IndexedDB). Talks to the bike over the ICG proprietary Nordic-UART protocol (documented in PROTOCOL.md).

Run it

Requires a Chromium browser (Web Bluetooth): desktop Chrome/Edge, or Android Chrome. Not iOS Safari.

pnpm install
pnpm dev            # http://localhost:5173

Web Bluetooth needs a secure context. localhost counts, so pnpm dev works offline with no certificates. For a production-ish local build:

pnpm build          # -> dist/ (static files, relative paths)
pnpm preview        # serves dist/ on localhost

Using it at the gym (no cloud)

• Laptop with Bluetooth (simplest): pnpm dev (or serve dist/), open http://localhost, tap Connect, pick the bike.
• Android phone: run the static dist/ from a local server on the phone (e.g. Termux python3 -m http.server) so it's localhost, or whitelist a laptop's LAN URL in chrome://flags#unsafely-treat-insecure-origin-as-secure.

Self-host

The hosted app above is the easiest way. If you'd rather run your own copy, it's a static site — nothing to configure, no backend, no database.

Docker — a prebuilt image (linux/amd64 + arm64) is published to the GitHub Container Registry:

docker run -d --name bikefit -p 8080:8080 --restart unless-stopped ghcr.io/libreble/bikefit
# → http://localhost:8080/

# compose.yaml
services:
  bikefit:
    image: ghcr.io/libreble/bikefit:latest
    ports: ["8080:8080"]
    restart: unless-stopped

The image serves the app at /. To serve it under a subpath behind your own proxy, build it yourself: docker build --build-arg BASE_PATH=/bikefit/ -t bikefit .

Build and host it yourself — any static web server works:

pnpm install --frozen-lockfile
pnpm build          # → dist/
# upload dist/ to nginx, Caddy, Netlify, Cloudflare Pages, a bucket, …

The build uses relative paths, so dist/ works from any path as is. Serve index.html and sw.js with Cache-Control: no-cache so updates reach installed copies. docker/nginx.conf.template is a working nginx example.

HTTPS is required. Web Bluetooth only works in a secure context. http://localhost counts, so the app works on the machine running it — but http://192.168.x.x:8080 from your phone will load and then refuse to connect. For phones, put it behind TLS: a reverse proxy with a real certificate (Caddy does this automatically for a domain), or tailscale serve.

Self-hosted copies keep their <link rel="canonical"> pointing at libreble.github.io, so search engines don't treat them as duplicates.

What it does (v1)

• Connect + auto-detect the protocol (ICG wired; FTMS/CPS are the next adapters).
• Live dashboard: power / cadence / HR / speed tiles + sparkline graphs.
• Debug logging (the reason v1 exists): every raw BLE notification is captured to IndexedDB as hex, decoded best-effort, with an "unparsed bytes" flag when a guess looks wrong.
• Save / export: write a self-contained SessionFile JSON (metadata + raw frames + decoded
  • summary) to disk for later analysis; re-export past sessions from IndexedDB.

Scripts

script	does
pnpm dev	Vite dev server
pnpm build	typecheck (tsc -b) + production build to dist/
pnpm preview	serve the built dist/
pnpm typecheck	types only
pnpm lint	oxlint
pnpm format	prettier write

Support

The app is free and stays that way. If you'd like to support the work anyway: a coffee on Ko-fi, or — honestly more useful — hardware. A device on the desk is how it gets an app; if you have one you'd like liberated, say so in a device request.