Writing
Notes on building real systems, voice AI, realtime, commerce architecture, and the decisions behind them.
- 6 min
Letting an AI assistant run a calling business without letting it guess
How I built an in-app agent that sets up and runs whole calling campaigns from one chat in Bangla or English: one capability registry, safety tiers, an Undo for everything, and the same tools served over MCP.
- 5 min
Building a wallet that cannot quietly lose money
Why the Smart Sheba wallet is an append-only ledger instead of a balance column, how commission payouts stay traceable to the purchase that caused them, and the integrity checks that prove every taka adds up.
- 6 min
Multi-tenant isolation in Postgres that fails closed
How the Commerce ERP keeps one merchant's orders and cash away from another with forced row-level security, a per-transaction tenant id, and composite foreign keys, plus the costs nobody mentions.
- 6 min
Building a voice AI that answers the phone in Bangla
What it takes to make an AI phone agent feel like a real call, latency budgets, a custom TTS voice, and why the SIP layer is the hard part.