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ayudaencali: a map that refuses to break

· 2 min read
Andrei Sherikhov
Andrei Sherikhov
18 y/o dev from Colombia

so this is the story of ayudaencali, a community emergency platform for santiago de cali. interactive map, a needs board where the neighborhood posts what it actually needs, and an ai assistant called CaliSolidaria IA on top of the real data.

the interesting part is not the features. it is that i built the whole thing around one rule:

nothing is allowed to leave a white screen.

the fallback chain​

every external service has a plan b (and sometimes a plan c):

  • database: supabase → in-memory cache → localStorage
  • ai: gemini → a local directory of emergency points, so the chat still answers
  • server: if the browser can't even reach the api, the ui reads what it already has

so if supabase explodes, the api answers from memory. if the api is down, the frontend reads localStorage. in no case does the user get nothing.

what it actually uses​

layerstuff
frontendreact 19 + typescript, vite, tailwind 4, leaflet
backendnode + express, and on vercel one function per route
datasupabase (postgresql + rls, 4 tables) with memory cache
authclerk (jwt verified on the server, never trusted from the body)
aigoogle gemini with a local fallback

the bits nobody puts in a demo​

  • rate limiting: 60 writes/min and 15 chat messages/min per ip. yes, i got tired of my own spam during testing.
  • rate limits change per environment: on vercel each function has its own counter, on express they share one. documented, not discovered in prod.
  • a real 404: public/404.html with noindex, served with an actual 404 status. the spa no longer returns 200 for a url that doesn't exist.
  • cookie consent that matters: third-party fonts only load if you say yes. i didn't want to be that site.
  • ci as a gate: tsc --noEmit → build → jsdom tests → a 60-check smoke test against the vercel routes. vercel only runs vite build, so this pipeline is the only thing stopping me from shipping broken types.

deploy​

free tier everything: vercel hobby (10 functions, 2 slots left), supabase, clerk, cloudinary for images. plus a dockerfile that runs the same server.ts if i ever want cloud run instead.

live: https://www.ayudaencali.lat · code: github.com/Sherikxd/AyudaEnCali