Overview
x402 on Quicknode provides wallet-authenticated, pay-per-request access to blockchain endpoints across all supported networks. Instead of creating an account and managing API keys, any client with a wallet and USDC can authenticate, purchase credits, and start making RPC calls immediately.
x402 is an open payment standard by Coinbase built on the HTTP 402 "Payment Required" status code. Client libraries handle the payment negotiation automatically.
x402 is an additive access method. It does not replace Quicknode's standard plans. Teams running production workloads benefit from standard plans with SLAs, dedicated support, and higher rate limits. x402 is designed for AI agents, rapid prototyping, and use cases where permissionless access is the priority.
x402 on Quicknode is currently in alpha.
# Fetch machine-readable x402 documentation for AI agents
curl https://x402.quicknode.com/llms.txt
How It Works
- Authenticate. Sign a message with your wallet (SIWE for EVM, SIWX for Solana) and exchange it for a JWT token at the
/authendpoint. - Make requests. Send requests to
POST /:networkwith the JWT in theAuthorization: Bearerheader. Requests work across JSON-RPC, REST, gRPC-Web, and WebSocket protocols. - Pay when prompted. When credits run out, the server returns HTTP 402. The
@x402/fetchlibrary automatically signs a USDC payment and retries the request. - Repeat. Credits are consumed per successful response. When exhausted, the next request triggers a new payment automatically.
Supported Protocols
x402 endpoints support the same protocols as standard Quicknode endpoints:
- JSON-RPC
- WebSocket
- REST
- gRPC-Web
Credit Model
x402 on Quicknode uses a drawdown credit model. You purchase credits upfront with USDC, and each successful response consumes credits based on the protocol used. When credits are depleted, the next request triggers an automatic payment for a new credit bundle.
Pricing
Note: Testnet usage is capped at 10,000 credits per wallet to prevent abuse.
Credit Consumption Rates
Error responses, JSON-RPC errors, and non-200 HTTP status codes are not metered.
Payment Network Decoupling
The payment network is decoupled from the endpoints you query. You can pay with USDC on Base and query Solana, or pay with Solana USDC and query Ethereum. The chain you pay on does not need to match the chain you are querying.
Supported Payment Networks
USDC payments are accepted on the following networks:
For testing, you can use testnet/devnet USDC to make requests against production endpoints. To get test USDC:
- Base Sepolia includes a built-in
/dripfaucet endpoint that provides free testnet USDC. - Circle provides a faucet across supported testnets.
Authentication
All endpoints except /auth require a JWT Bearer token. The /auth endpoint accepts three authentication paths:
- SIWE (EVM only): Post a signed EIP-4361 SIWE message. This is the original auth method and remains fully supported.
- SIWX/EVM: Same SIWE message format with
"type": "siwx"in the request body. - SIWX/Solana: A CAIP-122 / SIWS formatted message signed with Ed25519, encoded as Base58, with
"type": "siwx".
All paths require the following fields in the signed message:
domain(x402.quicknode.com)address(your wallet address)uri(https://x402.quicknode.com)version(1)chainId(the chain ID of the network you pay on)nonce(at least 8 random characters)issuedAt(current ISO 8601 timestamp, within 5 minutes).
The auth response returns a JWT that expires in 1 hour. Include Authorization: Bearer <JWT> on all subsequent requests.
x402 vs Standard Quicknode Plans
Resources
For managing Quicknode infrastructure through natural language, see Quicknode MCP. For giving AI coding agents accurate Quicknode API knowledge, see Blockchain Skills.
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