/
Request
Response · 200 OK
Try it · curl
Payment flow · x402
01 · QUOTE
Server replies 402
Body: x402Version, accepts[{scheme, network, asset, payTo, maxAmountRequired}], error
02 · PAY
Agent transfers USDC on Base
1 confirmation, ~2s on Base mainnet
03 · RETRY
Re-send with X-Payment header
base64url(JSON{x402Version, scheme, network, payload}) — server decodes + verifies on-chain
Error codes
| 200 | Success — JSON body matches the schema above |
| 402 | Payment required — body contains the quote and a fresh nonce |
| 400 | Invalid input format (missing file, malformed JSON, etc.) |
| 422 | Unprocessable — input was valid but extraction failed |
| 429 | Rate limit — same nonce reused or per-IP burst exceeded |
| 5xx | Upstream failure — no refund. Re-send with a new tx (replay protection: tx already consumed, sign a fresh one). |