One rail · two payers

Invisible payments —for you,and for your AI.

People check out with an email. AI agents pay their own x402 bills — under caps their owner controls. One balance, real evidence, no theatre.

Start building Set up an agent

The rail

One rail. Two payers.

Human checkoutemail → code → pay

Agent payment402 → policy → sign

Verifiedreal evidence only

One balance settles both. Buyers never see a wallet; agents never exceed their cap. Every settlement carries evidence you can independently verify.

For your AI

Your agent hits a paywall.
Tab handles the rest.

402200

01402 challengeA paid API answers with a payment challenge.
02Policy gatesCap, status, and kill-switch checked first.
03SignatureThe server wallet signs the exact amount.
04SettlementThe x402 facilitator settles USDC on-chain.
05200 OKThe request retries and simply succeeds.

No model in the loop, no blind allowance. A policy engine gates every request before any signature exists — and a kill switch stops new spending instantly.

For you

Checkout that feels like email, not a wallet.

Buyers type an email, enter a six-digit code, and pay. No extension, no seed phrase, no gas surprise. Balances live on real chains; complexity doesn’t reach the buyer.

Email + one-time code — nothing to install
One balance across supported chains
Test mode is always labeled, never simulated

Product illustration · no financial data

tabExample Merchant

$12.00

Base SepoliaSandbox funds — no real value

Product illustration · no financial data

amount: [amount] USDC
network: Base Sepolia · eip155:84532
payer: [agent address]
challenge: observed
policy: passed before signature
settlement: [transaction id]

Verified

Evidence, not theatre

Submitted is not settled. Tab shows the difference.

Every payment carries its own paper trail: the challenge, the policy decision, the signature, the settlement, and independent verification — each shown only when it really happened. No state is ever invented.

Real transaction ids, linked to public explorers
Verification is a separate, continuing check
Failures state whether money may have moved

Developers

A component for people.
A config for agents.

checkout.tsx

import { PayButton } from "@runtab/sdk";

<PayButton
  publishableKey="pk_test_…"
  intentUrl="/api/intent"
  onSuccess={(transactionId) => done(transactionId)}
/>

Drop-in email checkout. Package publication pending.

mcp.json

{
  "mcpServers": {
    "tab": {
      "command": "tab-agent",
      "env": {
        "TAB_API_BASE_URL": "https://app.example.com",
        "TAB_AGENT_KEY": "agent_sk_…"
      }
    }
  }
}

Point any MCP client at Tab. The agent pays x402 bills within its cap.

Built on the open internet

Base
Arbitrum One
Circle USDC

Open a tab.