x402-cli

Pay for x402 payment-gated HTTP endpoints using USDC stablecoins.

When to use

Use this tool when you need to access an API that returns HTTP 402 Payment Required with x402 payment requirements. The tool handles the full payment flow: probe → sign → pay → return response.

Prerequisites

Set EVM_PRIVATE_KEY environment variable with a wallet private key that holds USDC on the target network (e.g., Base Sepolia for testnet).

Usage

Probe an endpoint (check price without paying)

x402-cli --json --skip-verify <url>

Returns JSON with probe.paymentRequirements containing the price, network, and asset.

Pay and access an endpoint

x402-cli --json -y <url>

Returns JSON with payment.body containing the backend response and payment.paymentResponse containing the transaction hash.

POST with body

x402-cli --json -y -X POST -d '{"query": "hello"}' -H 'Content-Type: application/json' <url>

Self-signed TLS (local development)

x402-cli --json -y -k <url>

Exit codes

• 0 — Success (payment accepted or probe completed)
• 1 — Error (network, config, or unexpected failure)
• 2 — Payment rejected by facilitator
• 3 — Route is free (no payment needed)

JSON output structure

{
  "status": "accepted",
  "probe": {
    "statusCode": 402,
    "paymentRequired": true,
    "paymentRequirements": { "...x402 requirements..." }
  },
  "payment": {
    "statusCode": 200,
    "accepted": true,
    "signer": "0x...",
    "paymentResponse": { "success": true, "transaction": "0x...", "network": "eip155:84532" },
    "body": "...backend response..."
  }
}

Key fields to parse

• .status — "free", "payment_required", "accepted", "rejected", "error"
• .probe.paymentRequirements.accepts[0].amount — price in atomic units
• .probe.paymentRequirements.accepts[0].network — chain ID (e.g., eip155:84532)
• .payment.body — the actual backend response after payment
• .payment.paymentResponse.transaction — on-chain transaction hash