mppx.validateCredential

Validates a Credential without settling, reserving, or broadcasting payment.

Usage

Use validateCredential before a later broadcastCredential call when your application needs a non-mutating payment check.

import { Mppx, tempo } from 'mppx/server'
 
const mppx = Mppx.create({ methods: [tempo.charge()] })
 
const validation = await mppx.validateCredential('Payment credential="..."', {
  request: {
    amount: '0.10',
    currency: '0x20c0000000000000000000006a37DA5C996874BE', // OUSD on Tempo
    recipient: '0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266',
  },
  scope: 'GET /v1/report',
})
 
console.log(validation.source)
console.log(validation.payer)
0x70997970C51812dc3A010C7d01b50e0d17dc79C8

validateCredential is an advisory pre-check. Call broadcastCredential to accept payment.

Tempo charge and Session methods and EVM charge implement this lifecycle. For an EVM Credential, validation checks the signature, Challenge binding, payment terms, validity window, and source. Facilitator-backed methods also call the facilitator's non-mutating verification endpoint without settling. Custom EVM settlers remain responsible for chain-state checks and replay protection.

validation.payer is optional and comes from the verified payment payload. Tempo and EVM charges report the recovered payer address; its method-specific format may differ from the Credential source.

For a Session Credential, validation checks the channel, action, signature, and voucher state without accepting the voucher or updating channel accounting.

Return type

type ReturnType = Promise<Method.Validation>

Parameters

capturedRequest (optional)

• Type: Method.CapturedRequest

Authoritative request snapshot used by method hooks.

credential

• Type: string | Credential

Serialized Payment Credential field value or parsed Credential object.

meta (optional)

• Type: Record<string, string>

Expected Challenge metadata. Route comparison excludes the reserved _mppx_nonce issuance key; the Challenge HMAC still authenticates it. Clients return opaque unchanged.

realm (optional)

• Type: string

Expected Challenge realm.

request (optional)

• Type: Record<string, unknown>

Expected method request parameters.

scope (optional)

• Type: string

Expected route or resource scope bound to the Challenge.