Core Types

The SDK provides three core types that map directly to HTTP headers: Challenge, Credential, and Receipt.

from mpp import Challenge, Credential, Receipt

Parse a Challenge

challenge = Challenge.from_www_authenticate(
    'Payment id="...", realm="...", method="tempo", intent="charge", request="eyJ..."'
)

On the wire, request and optional opaque are base64url-encoded JSON strings in the WWW-Authenticate header. Challenge.from_www_authenticate(...) decodes them for application code.

Create and serialize a Credential

credential = Credential(
    id="challenge-id",
    payload={"type": "transaction", "signature": "0x..."},
    source="did:pkh:eip155:42431:0xa726a1...",
)
 
header = credential.to_authorization()

When a Credential echoes a Challenge, challenge.request and challenge.opaque stay in their base64url string form inside the serialized Authorization payload.

Parse and serialize a Receipt

receipt = Receipt.from_payment_receipt(header_value)
header = receipt.to_payment_receipt()