What it does
You add public Telegram channels you care about. Map Alerts reads their new posts, works out what happened and where, and puts each event on a map, so you can see what is going on near you instead of scrolling five feeds.
The pipeline
Each post goes through an OpenAI step that splits it into separate events, finds the place each one refers to and classifies it. The places are geocoded through an external API with a fallback, and unwanted or extremist channels are filtered out before anything reaches the map.
The backend began in Python with FastAPI. I rewrote it in Go and kept the /api/v1 contract identical, so the apps already in people’s hands didn’t need an update. Before shipping, I ran an end-to-end test against about 490 live events, which caught an off-by-one SwiftUI state bug nobody had noticed in manual testing.