Audit contractor payment applications API

Independently check a contractor payment application against the schedule of values, measured work, approved variations, previous certificates, retention rules, and deductions. Unsupported claims, duplicated work, unapproved variations, retention errors, and certificate mismatches are adjusted with calculation evidence. The recommended payable amount is for review only.

The Audit contractor payment applications operation is part of the Contractor Payment Application Audit API on BRAINIAC.software. Independently check a contractor payment application against the schedule of values, measured work, approved variations, previous certificates, retention rules, and deductions. Unsupported claims, duplicated work, unapproved variations, retention errors, and certificate mismatches are adjusted with calculation evidence. The recommended payable amount is for review only. It is exposed as POST /api/v1/construction-commercial/contractor-payment-application-audit and priced at $0.04 USDC on Base. Payment uses the x402 exact scheme: an unpaid call returns HTTP 402 with payment requirements; after paying the exact USDC amount, retry the same request with a payment-signature header and Idempotency-Key. No account and no API key are required. Data sources for this product: Caller-supplied contract terms, payment applications, schedule of values, certificates, measured quantities, variations, and deductions processed locally Limitations: Non-variation claims require measured_work. Unstated quantities are not invented. Unapproved variations are excluded. Approved variation claims are capped by approved_amount minus prior certificates. Retention uses floor(recommended_gross * retention_bps / 10000). The recommended payable amount is for review only and does not approve payment. Outputs are compliance prechecks, drafts, or data lookups for human review. They are not official determinations, legal advice, identity confirmation, or certified filings. Related operations in this group include the other resources on the product page. Open the group documentation for the full request schema, field notes, and response examples before integrating.

POST$0.04 USDC
/api/v1/construction-commercial/contractor-payment-application-audit

Example request

curl -i -X POST "https://www.brainiac.software/api/v1/construction-commercial/contractor-payment-application-audit" \
  -H 'content-type: application/json' \
  -H 'Idempotency-Key: <fresh-64-character-random-hex-key>' \
  --data-binary @- <<'JSON'
{
  "contract": {
    "id": "c1",
    "currency": "GBP",
    "retention_bps": 500,
    "retention_release_bps": 10000
  },
  "schedule_of_values": [
    {
      "id": "sov-1",
      "description": "Foundations",
      "contracted_amount": 100000
    },
    {
      "id": "sov-2",
      "description": "Frame",
      "contracted_amount": 200000
    }
  ],
  "payment_application": {
    "id": "app-3",
    "application_number": 3,
    "submitted_on": "2026-11-05",
    "claimed_retention_release": 1000,
    "lines": [
      {
        "id": "l1",
        "sov_item_id": "sov-1",
        "claimed_amount": 40000,
        "previously_certified_amount": 50000
      },
      {
        "id": "l2",
        "sov_item_id": "sov-2",
        "claimed_amount": 25000
      },
      {
        "id": "l3",
        "sov_item_id": "sov-2",
        "claimed_amount": 10000,
        "variation_id": "var-1"
      }
    ]
  },
  "previous_certificates": [
    {
      "id": "cert-1",
      "certificate_number": 1,
      "certified_on": "2026-10-01",
      "retention_held": 2500,
      "lines": [
        {
          "sov_item_id": "sov-1",
          "certified_amount": 50000
        }
      ]
    }
  ],
  "measured_work": [
    {
      "id": "m1",
      "sov_item_id": "sov-1",
      "measured_amount": 80000
    },
    {
      "id": "m2",
      "sov_item_id": "sov-2",
      "measured_amount": 20000
    }
  ],
  "variations": [
    {
      "id": "var-1",
      "sov_item_id": "sov-2",
      "approved_amount": 8000,
      "approved": false,
      "description": "Extra steel"
    }
  ],
  "deductions": [
    {
      "id": "d1",
      "amount": 500,
      "reason": "Defects"
    }
  ]
}
JSON

An unpaid probe returns HTTP 402 with x402 payment requirements. After paying the exact USDC amount on Base, retry the identical request with a payment-signature header.

FAQ

  • Do I need an API key? No. Pay the listed USDC amount with x402.
  • What network? Base (eip155:8453), USDC.
  • Is this an official determination? No. Results are for human review against the cited sources.

    Related APIs

    Contractor Payment Application Audit APIFull docsHow it works