Case study
Mesob
A shared inbox and AI triage for businesses that sell over Telegram. Messages are deduplicated, queued in Postgres and triaged rules-first, so most traffic never reaches a model and nothing invents a price.
- Year
- 2026
- Role
- Solo build
- Status
- Open source
A large share of Ethiopian retail runs through Telegram DMs. That works until it doesn’t: one inbox on one phone, no history when a second person helps out, no way to tell an unanswered question from a handled one. Customers who don’t get an answer in a few minutes go to the next shop.
Mesob puts a real inbox behind that phone without asking the merchant to change how they work, or the customer to install anything. It is a working backend slice, not a mockup: ingest, queue, triage, outbox and delivery all run, and 47 tests cover the concurrency behaviour that matters.
Telegram Business, not a bot
The Business API lets a bot act as the account owner, so customers keep messaging the same person and see the shop’s own name. It also means Mesob sees both sides of the conversation: a message from the owner is the merchant typing by hand, which is a free and exact signal to mute the assistant in that thread.
Postgres is the queue
FOR UPDATE SKIP LOCKED gives competing consumers without a broker, and keeps job rows in
the same transaction as the data they describe, which is what makes the outbox pattern
hold. Four workers claiming 40 jobs claim each one exactly once.
Telegram retries anything that isn’t a 2xx, so idempotency lives at two layers: the update id and the message id. Replaying a whole morning of traffic concurrently stores nothing twice.
Triage, cheapest first
Rules, then cache, then model. Merchant traffic is repetitive, so the free tiers answer most of it; in the demo, 7 of 8 messages never reach a model. The bill scales with novelty, not volume, and a model outage degrades to the rules guess and a human queue.
The rules read Amharic in Ge’ez script, Amharic in Latin letters (“sint new?”), English, and mixtures of all three.
The assistant may not invent facts
Only greetings and receipt acknowledgements are sent automatically, because both can be answered without knowing a single business fact. Prices, stock, addresses and delivery times are drafted and held for a person. A confident wrong number costs a sale; silence costs a minute.