x402 Dev Tools

Asks the public x402 facilitators (CDP, x402.org, PayAI, x402.rs, Dexter, Daydreams, OpenX402, Mogami, Heurist) for GET /supported right now: whether each answers, its latency, and the x402 versions, schemes and networks it settles. Pass network to keep only those that support it.

Decodes a PAYMENT-REQUIRED, PAYMENT-SIGNATURE or PAYMENT-RESPONSE header (x402 v2, or X-PAYMENT / X-PAYMENT-RESPONSE of v1), base64 or JSON, detecting which it is. Explains it in plain terms (price in dollars, network, payer and payee, validity window, explorer link) and lists problems: wrong USDC EIP-712 domain, expired or not-yet-valid authorizations, amount or payee mismatches, missing Bazaar extension.

Checks an x402 API origin the way x402scan, the CDP Bazaar and agents read it: fetches /openapi.json and /.well-known/x402, then calls each paid route without paying (up to 30) and decodes its 402. Reports routes that do not answer 402, missing or v1-only PAYMENT-REQUIRED headers, prices that differ from the OpenAPI document, resource URLs that differ from the route, wrong USDC EIP-712 domains, missing Bazaar extensions and missing descriptions.

Reference for x402 sellers and clients: each network's CAIP-2 id, v1 name, chain id, USDC contract, decimals, the EIP-712 domain name and version its USDC signs over (read from the contracts), and explorer. Pass network to get one.

Generates the discovery documents directories and agents read for a list of paid endpoints (up to 100): an OpenAPI 3.1 document with x-payment-info prices and examples, the /.well-known/x402 resource list and an llms.txt, in the shape x402scan and the CDP Bazaar index.

Encodes a PaymentRequired, PaymentPayload or settlement response object as the base64 value of its x402 header, for hand-written servers, clients and tests, and reports the same problems /v1/decode finds.

Builds an x402 v2 PaymentRequired object for a price in dollars on one or more networks, with the right USDC contract, atomic amount and EIP-712 domain (name and version) for each, plus the base64 PAYMENT-REQUIRED header value to send with the 402.