t402
HTTP-native stablecoin payment protocol for AI agents
Resources
17Install
npx skillscat add t402-io/t402 Install via the SkillsCat registry.
SKILL.md
t402 Payment Skill
Teach your AI agent to pay for web resources using USDT/USDC stablecoins across 25+ blockchain networks.
What You Can Do
- Pay for HTTP resources — automatically handle 402 Payment Required responses
- Check balances — query wallet balances across all supported networks
- Bridge tokens — move USDT0 between chains via LayerZero
- Swap tokens — exchange tokens via DEX aggregators
- Verify agents — check ERC-8004 on-chain identity and reputation
- Monitor payments — track payment flows and metrics
How HTTP 402 Payment Works
1. Request a resource: GET https://api.example.com/data
2. Receive 402 response: { amount: "1000000", asset: "USDC", network: "eip155:8453" }
3. Sign payment: EIP-3009 TransferWithAuthorization (gasless)
4. Retry with payment: GET /data + PAYMENT-SIGNATURE header
5. Receive resource: 200 OK + dataThe entire flow happens in a single request-response cycle. No accounts, API keys, or checkout flows needed.
Available MCP Tools
Core Payment (always available)
| Tool | Description |
|---|---|
t402/getBalance |
Get token balances on a specific network |
t402/getAllBalances |
Get balances across all networks |
t402/pay |
Execute a stablecoin payment |
t402/payGasless |
Pay without gas (ERC-4337) |
t402/getTokenPrice |
Get current token prices |
t402/getGasPrice |
Get gas prices per network |
t402/estimatePaymentFee |
Estimate payment cost |
t402/compareNetworkFees |
Find cheapest network |
t402/getBridgeFee |
Quote a cross-chain bridge |
t402/bridge |
Execute cross-chain transfer |
t402/quoteBridge |
Get reusable bridge quote |
t402/executeBridgeQuote |
Execute from quote |
WDK Wallet (requires seed phrase)
| Tool | Description |
|---|---|
wdk/getWallet |
Get wallet info |
wdk/getBalances |
Multi-chain balances |
wdk/transfer |
Send stablecoins |
wdk/swap |
Swap tokens (Velora) |
wdk/quoteSwap |
Get swap quote |
wdk/executeSwap |
Execute from quote |
t402/autoPay |
Smart auto-payment — fetch URL, handle 402, pay, return content |
Agent Identity (ERC-8004)
| Tool | Description |
|---|---|
erc8004/resolveAgent |
Look up agent identity |
erc8004/checkReputation |
Query reputation score |
erc8004/verifyWallet |
Verify payment address |
Unified (advanced)
| Tool | Description |
|---|---|
t402/smartPay |
Intelligent payment routing |
t402/paymentPlan |
Multi-step payment planning |
Supported Networks
EVM (25 mainnet chains)
Ethereum, Base, Arbitrum, Optimism, Polygon, Avalanche, BNB, Berachain, Celo, Ink, Unichain, MegaETH, Flare, Kaia, Mantle, Sei, Conflux, Monad, Rootstock, XLayer, Fantom, HyperEVM, Plasma, Stable, Corn
Non-EVM
Solana, TON, TRON, NEAR, Aptos, Tezos, Polkadot, Stacks, Cosmos, Bitcoin, Lightning, Stellar, Spark
Supported Tokens
- USDT0 — Tether omnichain (EIP-3009, gasless)
- USDC — USD Coin (EIP-3009)
- USDT — Legacy Tether (approve+transferFrom)
- USAT — Tether America USD
Security Rules
- Always confirm before payment — never auto-execute without user approval
- Never expose seed phrases — use environment variables
- Verify recipients — use
erc8004/verifyWalletbefore paying unknown agents - Set spending limits — use the policy engine for budget enforcement
- Check prices first — use
t402/estimatePaymentFeebefore committing
Quick Start
As an AI Agent (MCP)
npm install @t402/mcpConfigure in your MCP client with a WDK seed phrase. The t402/autoPay tool handles the entire 402 flow automatically.
Programmatic (TypeScript)
import { createT402Client, wrapFetchWithPayment } from "@t402/core";
const client = createT402Client({ signer: myWallet });
const fetch402 = wrapFetchWithPayment(fetch, client);
// Just fetch — payment happens automatically on 402
const data = await fetch402("https://paid-api.example.com/data");