Barker: Crowdsourced Bus Tracker
Live tracker for buses that have no GPS of their own, fed by the commuters on board. First line: Ternate to PITX.
Many buses have no public tracker, so Barker lets the riders on board become the bus's eyes. Commuters waiting ahead see where the next bus is, how many minutes away, whether it has seats, and how many people are sharing, and they can ask for an alert at 3, 5, 10, or 15 minutes out. No account, and it works in the phone's browser or as an installed app.
The backend is a Cloudflare Worker with Durable Objects as the live WebSocket hub, D1 for storage, and short-lived HMAC tokens. Alerts are hand-encrypted Web Push (RFC 8291), and the Android app is a Capacitor shell with background GPS, so sharing keeps going with the screen off.
A bus line is just data, so more routes can be added; the first is Saulog Transit from Ternate to PITX. Designed to run at $0 for 1k daily users on Cloudflare's free tier.