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OpenAPI Specification

openapi: 3.2.0
info:
  title: Quartermaster Payment Proof API
  version: 1.6.0
  description: Small, reliable utility APIs for AI agents. Paid endpoints charge per call in USDC over the x402 protocol (HTTP 402 flow) - no accounts, no API keys. Free endpoints are open.
  contact:
    url: https://quartermaster.surewhynot.app
servers:
- url: https://quartermaster.surewhynot.app
tags:
- name: Payment Proof
paths:
  /v1/payment-proof:
    get:
      summary: Verify an x402 settlement on Base or Solana (composite)
      description: Confirms the transaction succeeded (Base 0x hash or Solana base58 signature), decodes its USDC transfers (event logs on Base, net token-balance deltas on Solana), and optionally asserts the receiving wallet and amount.
      parameters:
      - name: hash
        in: query
        required: true
        description: 0x Base transaction hash or base58 Solana signature
        schema:
          type: string
      - name: payTo
        in: query
        required: false
        description: 'Optional: assert USDC was received by this wallet (0x on Base, base58 on Solana)'
        schema:
          type: string
      - name: amount
        in: query
        required: false
        description: 'Optional: assert the USDC amount (human decimal)'
        schema:
          type: string
      responses:
        '200':
          description: Verification verdict
          content:
            application/json:
              schema:
                type: object
        '402':
          description: Payment required
          content:
            application/json:
              schema:
                type: object
        '404':
          description: Not found
          content:
            application/json:
              schema:
                type: object
      x-payment:
        protocol: x402
        price: $0.003
        currency: USDC
        note: Unpaid requests receive 402 Payment Required with machine-readable payment requirements.
      tags:
      - Payment Proof
      operationId: getV1PaymentProof
      x-operation-id-source: derived
externalDocs:
  description: 'Buyer quickstart: how to pay with x402'
  url: https://quartermaster.surewhynot.app/buyers