ArcPay — x402 API

Pay-per-use API endpoints using the x402 standard. Any x402-compatible agent can pay USDC to resolve Discord usernames to Arc wallet addresses.

Live on Arc Testnet

How it works

Agent calls the endpoint — any x402-compatible client requests a resource

ArcPay returns 402 — with payment details, price, and wallet address

Agent signs EIP-3009 — offchain authorization, zero gas

Agent retries with X-PAYMENT header — ArcPay verifies and returns data

Circle settles in bulk — thousands of payments in one onchain transaction

GET /api/x402/lookup $0.001 USDC

Look up a single Discord username and get their Arc wallet address.

GET https://arcpay.one/api/x402/lookup?username=sleek

Response:
{
  "discord_username": "sleek",
  "wallet_address": "0x04eb...",
  "network": "ARC-TESTNET"
}

GET /api/x402/resolve $0.005 USDC

Resolve up to 10 Discord usernames at once.

GET https://arcpay.one/api/x402/resolve?usernames=sleek,tohnyrose

Response:
{
  "resolved": {
    "sleek": { "wallet_address": "0x04eb..." },
    "tohnyrose": { "wallet_address": "0xd8fd..." }
  }
}

GET /.well-known/x402.json Free

Discovery endpoint — agents use this to automatically find ArcPay's paid APIs.