x402 nanopayments

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Edge RPC accepts pay-per-request payments over the x402 protocol, settled through Circle Gateway. Fund a USDC balance once with Circle and pay per call against any supported chain, with no Goldsky account, no API key, and no invoice. x402 is designed for autonomous agents. SDK clients handle the full handshake transparently.

Pricing

$5 per million requests, all methods, all chains. Each call debits 5 atomic USDC ($0.000005) from your Circle Gateway balance. Settlement is gasless on your side, and Circle batches settlements on Goldsky’s side.

Endpoint

Edge RPC endpoints follow a single URL pattern, with the chain ID in the path:

https://edge.goldsky.com/standard/evm/{chainId}

To discover every chain Edge serves, hit edge.goldsky.com with no path. It returns a JSON list of every supported network, with CAIP id, alias, block time, and health status:

curl https://edge.goldsky.com | jq '.standard[] | {id, alias, state}'
# {"id": "evm:1",     "alias": "ethereum-mainnet", "state": "OK"}
# {"id": "evm:8453",  "alias": "base",             "state": "OK"}
# {"id": "evm:42161", "alias": "arbitrum",         "state": "OK"}
# ...

Supported chains for x402 payments

The chain you pay on is independent of the chain you query. The table below lists the 11 networks you can settle payments on — it mirrors the live list at https://gateway-api.circle.com/v1/x402/supported. You can pay with USDC on any one of them and then query any chain Edge serves, including chains that aren’t in this table and chains with no USDC of their own. For example: fund on Base, then read Robinhood Chain — one Gateway balance covers every chain Edge supports, and no API key is involved.

Network	CAIP id	USDC contract
Ethereum	`eip155:1`	`0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48`
Base	`eip155:8453`	`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`
Arbitrum One	`eip155:42161`	`0xaf88d065e77c8cC2239327C5EDb3A432268e5831`
Optimism	`eip155:10`	`0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85`
Polygon	`eip155:137`	`0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359`
Avalanche C-Chain	`eip155:43114`	`0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E`
Unichain	`eip155:130`	`0x078D782b760474a361dDA0AF3839290b0EF57AD6`
Sonic	`eip155:146`	`0x29219dd400f2Bf60E5a23d13Be72B486D4038894`
World Chain	`eip155:480`	`0x79A02482A880bCE3F13e09Da970dC34db4CD24d1`
Sei EVM	`eip155:1329`	`0xe15fC38F6D8c56aF07bbCBe3BAf5708A2Bf42392`
HyperEVM	`eip155:999`	`0xb88339CB7199b77E23DB6E890353E22632Ba630f`

You only need a Circle Gateway USDC deposit on one of these chains. The endpoint advertises every chain in its 402 response, and SDK clients pick whichever you’re funded on.

Quickstart

1. Fund a Circle Gateway deposit

Use the Circle Gateway dashboard, or do it directly via the SDK:

import { GatewayClient } from "@circle-fin/x402-batching/client";

const gateway = new GatewayClient({
  chain: "base",                     // any supported chain
  privateKey: process.env.PK as `0x${string}`,
});

await gateway.deposit("1");          // 1 USDC = 200,000 Edge requests

Your deposit takes a few minutes to reflect in Circle’s /v1/balances API after the on-chain transaction confirms.

2. Pay for an Edge request

pay() handles the full 402 → sign → retry flow for you:

const { data, formattedAmount, transaction } = await gateway.pay(
  "https://edge.goldsky.com/standard/evm/1",
  {
    method: "POST",
    headers: { "content-type": "application/json" },
    body: { jsonrpc: "2.0", id: 1, method: "eth_chainId", params: [] },
  },
);

console.log("paid", formattedAmount, "USDC →", JSON.stringify(data));
// paid 0.000005 USDC → {"jsonrpc":"2.0","id":1,"result":"0x1"}

That’s it. No Goldsky account, no secret query parameter, no invoice. Your wallet address becomes your identity for rate limiting and metrics.

How it works

x402 is an HTTP protocol layered on top of standard requests. The full handshake:

Initial request returns 402

Your client sends an unauthenticated request. Edge responds with HTTP 402 and a body listing every accepted (chain, asset) option:

{
  "x402Version": 2,
  "error": "Payment required for this resource",
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:8453",
      "amount": "5",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "payTo": "0x87aB362fEF2106d24762289410a18e7c42304C68",
      "maxTimeoutSeconds": 604800,
      "extra": {
        "name": "GatewayWalletBatched",
        "version": "1",
        "verifyingContract": "0x77777777dcc4d5a8b6e418fd04d8997ef11000ee"
      }
    }
    // ...one entry per supported chain
  ]
}

Sign an EIP-712 authorization

Your client picks an accepts entry it can satisfy (typically the chain your Gateway deposit lives on) and signs an EIP-712 TransferWithAuthorization message against the GatewayWalletBatched contract from the extra block.

Retry with Payment-Signature header

Your client base64-encodes the signed payload and resends the original request with one extra header:

POST /standard/evm/1
Content-Type: application/json
Payment-Signature: <base64(payment payload)>

Edge forwards the payment to Circle’s facilitator for settlement, then proxies the RPC request to upstream providers and returns the response with HTTP 200.

A successful settlement debits your Circle Gateway balance and emits a settlement receipt back in the response headers. Failed settlements (insufficient balance, expired authorization, etc.) return a 402 again so you can pick a different chain or top up.

Limits and operational notes

Authorization validity window: Circle Gateway requires the signed authorization’s validBefore to be at least ~4 days in the future. Edge advertises maxTimeoutSeconds: 604800 (7 days) so SDK defaults work out of the box.

Edge RPC

Reference

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Pricing

Endpoint

Supported chains for x402 payments

Quickstart

1. Fund a Circle Gateway deposit

2. Pay for an Edge request

How it works

Limits and operational notes

See also

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​Pricing

​Endpoint

​Supported chains for x402 payments

​Quickstart

​1. Fund a Circle Gateway deposit

​2. Pay for an Edge request

​How it works

​Limits and operational notes

​See also

Pricing

Endpoint

Supported chains for x402 payments

Quickstart

1. Fund a Circle Gateway deposit

2. Pay for an Edge request

How it works

Limits and operational notes

See also