Crema — Meraki Gen 2 bean advisor

A mobile-first web app. Search any coffee (a roaster and bag, or an origin and process) and get:

• what the coffee is: origin, region, process, variety, altitude and roast level
• how it tastes: tasting notes, a flavour radar (acidity, sweetness, body, creaminess, bitterness, finish) and a description of its character
• a starting recipe for the Meraki Gen 2: dose, yield, ratio, brew temperature, pre-infusion (pressure and seconds), target shot time and grind direction
• recipes for 12 drinks (ristretto, espresso, doppio, lungo, americano, long black, macchiato, cortado, piccolo, flat white, cappuccino, latte), including milk volume and the auto-steam temperature
• dial-in fixes for this specific coffee, rest days, water, basket and milk tips

Every lookup is kept on the device (the 20 most recent coffees, in localStorage), so reopening one from Recent lookups or searching for it again costs nothing and works offline. Research again on a recipe runs a fresh lookup. Saved coffees live on the device too. The Guide tab gives the classic ratios for every drink.

How it works

POST /api/brew asks Claude Opus 5.5 to research the coffee with web search. It goes through OpenRouter when OPENROUTER_API_KEY is set (model anthropic/claude-opus-5.5, OpenRouter's openrouter:web_search tool), or directly to Anthropic with ANTHROPIC_API_KEY. A lookup takes about 15–35 s and costs roughly $0.05–0.10. The answer is validated against a zod schema (lib/schema.ts) and clamped to what the Meraki Gen 2 can actually do (85–96 °C, 14–22 g, 1:1–1:3.5, pre-infusion 3 or 4 bar for 5–15 s, or off). The drink recipes are then derived in code from the base recipe (lib/drinks.ts), so ratios stay consistent.

Grind advice is relative ("2 steps finer than your usual medium-roast setting"). Meraki doesn't publish the numbering of its 45 grinder steps, so the app never makes up an absolute number.

Run locally

npm install
cp .env.example .env.local   # add OPENROUTER_API_KEY (or ANTHROPIC_API_KEY), or set DEMO_MODE=1
npm run dev                  # http://localhost:3000

To open it on your phone over Wi-Fi, run npm run dev -- -H 0.0.0.0 and visit http://<your-mac-ip>:3000.

Deploy to Vercel

1. Push this repository to GitHub and import it at vercel.com/new (framework: Next.js).
2. Under Settings → Environment Variables, add OPENROUTER_API_KEY and APP_ACCESS_CODE. Optionally add OPENROUTER_MODEL.
3. Deploy, open the URL on your phone and choose Add to Home Screen. Enter the access code once.

Lookups take about 20–40 s, and the route allows up to 120 s (maxDuration).

Tests

npm test          # unit tests: drink derivation, schema clamping, Claude client, API handler
npm run e2e       # Playwright at iPhone size against a production build in demo mode