Minimal Next.js 16 app showing live London Underground arrival boards powered by the TfL Unified API.

npm install
npm run dev

Open http://localhost:3000.

• Arrivals: https://api.tfl.gov.uk/StopPoint/{naptanId}/Arrivals
  • Returns arrival predictions (sorted by timeToStation seconds)
  • No API key needed at low volume (~50 req/min/IP unauthenticated)
• Station search: https://api.tfl.gov.uk/StopPoint/Search/{query}?modes=tube,dlr,overground,elizabeth-line&maxResults=6

• app/page.tsx — single client component (hooks + fetch)
• lib/stations.ts — preset NaPTAN IDs + line-colour map
• Up to 4 stations shown simultaneously
• 30 s poll interval per board, 400 ms debounce on search
• Selected stations persisted to localStorage under tfl:stations

• app/api/arrivals/[id]/route.ts proxy to keep a TfL app_key server-side
• Platform-level grouping for Elizabeth line / Overground
• iOS home-screen web-clip layout
• Custom domain via vercel domains add

Data © tfl.gov.uk, Open Government Licence.