deliberately brokenMPP

MPP challenge with an empty id

An MPP challenge carrying id="", which the draft says a server must never send.

Your client should Reject it, as the draft requires of every parser.

Protocol: MPP
Network: Base Sepolia
Price: 0.0001 USDC
Scheme: exact
Facilitator: x402.org
Behavior: Empty challenge id

The MPP challenge carries id="". The draft says a server must never send this and a client must reject it, so an accepting parser is out of spec.

Customize this test

Your endpointEmpty challenge id

/api/mpp?quirk=empty-id

Try it

curl -i "https://test402.com/api/mpp?quirk=empty-id"

Returns 402 whose WWW-Authenticate has an empty id parameter. Reference implementations have disagreed with the draft and with each other here.

Response it will return (HTTP 402)

WWW-Authenticate: Payment id="", realm="test402.com", method="evm", intent="charge", request="eyJhbW91bnQiOiIxMDAiLCJjdXJyZW5jeSI6IjB4MDM2Q2JENTM4NDJjNTQyNjYzNGU3OTI5NTQxZUMyMzE4ZjNkQ0Y3ZSIsIm1ldGhvZERldGFpbHMiOnsiY2hhaW5JZCI6ODQ1MzIsImNyZWRlbnRpYWxUeXBlcyI6WyJhdXRob3JpemF0aW9uIiwidHJhbnNhY3Rpb24iXSwiZGVjaW1hbHMiOjYsInBlcm1pdDJBZGRyZXNzIjoiMHgwMDAwMDAwMDAwMjJENDczMDMwRjExNmRERUU5RjZCNDNhQzc4QkEzIn0sInJlY2lwaWVudCI6IjB4MDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDQwMiJ9", expires="2026-01-01T00:05:00Z"

{
  "type": "https://paymentauth.org/problems/payment-required",
  "title": "Payment Required",
  "status": 402,
  "detail": "test402 challenge",
  "note": "test402 scenario. quirk=empty-id"
}