What is Tab
One payment rail, two kinds of payers — humans pay with an email, AI agents pay x402 under a hard cap.
Tab is a payments product with one rail and two payers:
- Humans check out with an email. No wallet extension, no seed phrase — a one-time code creates a wallet behind the scenes and the payment settles in USDC.
- AI agents pay x402
402 Payment Requiredresponses by themselves, through an MCP proxy that enforces a spending cap outside the model. The agent never holds a key.
Both payers settle on the same rail and leave the same evidence: a receipt with an amount, a network, and a transaction hash.
The three surfaces
| Surface | Who it's for | What it does |
|---|---|---|
<PayButton> | Your customers | Embedded checkout: email → code → pay |
| Merchant dashboard | You | Keys, webhooks, transactions, go-live |
| Agent dashboard | Agent owners | Provision, cap, fund, connect, revoke |
Test mode is honest
Tab's test mode runs on Base Sepolia with real on-chain test funds — never simulated balances under a real-money label. Everything labeled "Sandbox funds — no real value" is exactly that. Live execution is gated until the production money-mover spike is verified; test mode is fully functional end to end.
Where to start
- Selling something? Start with the Quickstart.
- Wiring an agent? Start with Agents & x402.
- Want free test funds? See Test funds.