Example app

The demo module of the January Android SDK repository is a Jetpack Compose app that uses every resource: food search with full foods and servings, food analysis and the native scanner, restaurants, food logs, a Tracking tab with each day's food, water, and weight and week, month, and year charts, glucose prediction, and user and timezone settings. It creates a new client whenever you switch users, as Client lifecycle describes.

Open the repository in Android Studio, or set ANDROID_HOME for command-line builds.

1. Start the token relay

The demo gets its tokens from the token relay. Starting it walks you through creating an API key and switching on Enable client tokens in the Developer Dashboard. The key stays in the relay's .env file and never enters the app.

2. Point the demo at the relay

Add the relay's values to the repository's local.properties, which is untracked. Never commit it.

Where the relay runs	january.partnerTokenUrl	january.partnerSessionToken
This computer, used from the emulator	http://10.0.2.2:8787/api/january/client-token	Leave it out
Your Wi-Fi, used from a device (HOST=0.0.0.0 ./start.sh)	The Wi-Fi URL the relay prints	The token the relay generates
Hosted (Vercel guide)	The relay's HTTPS token URL	Its RELAY_TOKEN

january.partnerTokenUrl=http://10.0.2.2:8787/api/january/client-token

The demo sends a POST with the selected end-user ID in January-End-User-ID, plus Authorization: Bearer <january.partnerSessionToken> when that is set. Its debug build allows cleartext traffic, so the local http:// URL works.

3. Build and run

./gradlew :demo:installDebug

Search for a food, open it, change its serving, and try the scanner. If the token URL is missing, the demo says so instead of choosing a default.

Without the relay

For the quickest local test, leave out the token values and set january.apiKey=sk-… in local.properties. Debug builds use the key directly and show a warning. Never commit the key, share the APK, or distribute the build.

Next: Client lifecycle