Paid channel access on TON

The task

Show, as an open project, how to sell access to a private Telegram channel for crypto with no payment provider and no manual checks. The blockchain is the source of truth: anyone can verify a subscription without trusting the server.

What I built

• Two Tact smart contracts. The main one takes payments and deploys a small per-subscriber contract that stores the expiry date. Renewing early adds to the time left, and underpayments are bounced back automatically.
• The bot admits people to the channel only through join requests. Before approving, it reads the subscription from the blockchain, and every minute it removes members whose subscription has expired.
• A Mini App that looks like Telegram itself: subscription status, payment with TON Connect, confirmation and a button to open the channel. Colors follow the user’s Telegram theme.
• The server verifies Telegram’s signature on every Mini App request, so nobody can view or pay for a subscription as someone else.
• Deployed to testnet and tested with a real payment. It caught a bug the tests had missed: the wallet took the fee out of the amount and the contract bounced the payment. The server now asks for a 0.01 TON reserve, covered by its own test.

Results in numbers