Check field compatibility before a data migration

Deterministically gate caller-supplied field contracts before ingestion, migration, CI deployment, or machine-to-machine handoff; returns stable incompatibility codes and remediation actions without fetching data or validating API behavior.

0.003 USDC / call · Base · x402 v2 exact

Version 1.0.0. Demand unvalidated. Catalogue availability does not prove paid fulfilment.

Request

POST https://api.zfinia.com/x402/v1/data-compatibility-checker

{
  "contract_version": "1",
  "comparison_mode": "backward_compatible",
  "canonicalization": "exact",
  "source_fields": [
    {
      "name": "id",
      "type": "string",
      "required": true,
      "nullable": false
    }
  ],
  "target_fields": [
    {
      "name": "id",
      "type": "string",
      "required": true,
      "nullable": false
    }
  ]
}

1. Send the example as an application/json POST without payment to receive HTTP 402.
2. Inspect Payment-Required and confirm the network, asset, recipient and amount using your own x402 client.
3. Your client authorizes payment and retries the same POST. A successful paid response returns the result. A 402 is not a delivery.

GET is an unpaid payment challenge probe. Paid delivery uses POST.

Machine clients: website catalogue JSON · MCP challenge handoff. MCP does not hold a buyer wallet or make payments for you.