I built a campus marketplace that runs entirely inside Telegram

#webdev #programming #showdev #telegram

I built a campus marketplace that runs entirely inside Telegram

Students at my campus run their entire economy through scattered WhatsApp groups. Buying, selling, events, announcements — all fragmented, none verifiable. Asking them to install a new app never works.

So I built TrybeOS, a campus operating system that lives inside a Telegram bot. Open it: https://trybe-os.vercel.app

The product

TrybeOS is a Telegram Mini App covering four things:

Marketplace — buy, sell, rent and hire services between verified students
Events & announcements — campus events, deadlines and official notices in one feed
Anonymous messages — rate-limited "whispers" so people can speak honestly without abuse
Match — study groups and campus friendships between verified students

Verification gates everything: confirm a campus email or upload a student ID before you can post. That single rule is what stops it turning into another spam channel.

The stack

Frontend: React 18 + Vite, built to a static bundle
Backend: FastAPI with async endpoints and per-user rate limiting
Database: Postgres (Supabase) in production, SQLite locally
Deploy: Vercel, with a nightly cron for match nudges
Auth: Telegram Web App SDK — no separate signup flow

The bot sets up a config object (window.__TRBY_CONFIG__) at serve time, so the same build works across dev and prod without rebuilding.

The hard parts

Anonymous posting that stays civil — rate limiting per user plus server-side checks. Balance freedom against spam.
Student verification — matching IDs/campus emails without hoarding sensitive data.
Events vs announcements — one model (is_hosting) that handles both "I'm hosting this" and "sharing a notice", so the feed stays coherent.

What I learned

Solo-building a product end-to-end is mostly about scope control. The version that shipped is a fraction of what I sketched — and that is the version people actually use.