Skip to main content

​
OpenAPI Reference

The OpenAPI reference is the exact HTTP contract for direct PayChain integrations. Use it when you need endpoint paths, request bodies, response schemas, query parameters, and error shapes.
Reference note: The OpenAPI contract covers the public merchant API. Use it alongside the flow guides so schemas are paired with fulfillment and reconciliation guidance.

​
Where to find it

​
How to use OpenAPI with these docs

  • Start with Payment flows to choose the right integration pattern.
  • Use SDK guide if you are building with Node.js or TypeScript.
  • Use REST API guide if you are calling PayChain over HTTPS directly.
  • Use this OpenAPI reference when you need exact fields, schemas, and path details.

​
Included surfaces

The external contract includes the core merchant integration surfaces:
  • Businesses.
  • Customers.
  • Invoices.
  • Public invoice status.
  • Balances.
  • Transactions.
  • Withdrawals.
  • Webhook configuration and delivery events.
  • Networks.
  • Tokens.
  • Prices and supported assets.
For human-readable network guidance, see Supported networks and tokens.

​
Not covered by OpenAPI

Some product actions are handled through the dashboard or support-assisted workflows instead of the public merchant API. Use the dashboard for account settings, API key management, billing changes, and payout-route administration unless a public API endpoint is documented.

​
Authentication

External API requests use the x-api-key header.
Use Idempotency-Key on mutating requests.

​
Production use

When generating clients from OpenAPI, keep these integration rules in your application code:
  • Store API keys only on your backend.
  • Send Idempotency-Key on mutating requests.
  • Verify webhook signatures with the raw body.
  • Fetch the canonical resource before fulfilling customer value.
  • Handle unknown error codes and enum values gracefully.