MP
API Reference
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Getting started
  • Introduction
  • Quickstart (15-min walkthrough)
  • Postman
  • Environments
Core
  • Authentication
  • Versioning
  • Errors
  • Rate limits
  • Idempotency
  • Pagination
  • Security model
  • Webhooks & signing
  • paymentData shapes by method
  • Multi-merchant / multi-shop
  • Payment lifecycle
Endpoints
  • GET /ping
  • GET /me
  • POST /api/v1/checkout/sessions
  • POST /api/v1/payments
  • GET /api/v1/payments/{id}
  • GET /api/v1/payments
  • POST /payments/{id}/refund
  • GET /api/v1/payment-methods
  • GET /balance
  • POST /webhooks (register)
  • GET /webhooks (list)
  • GET /webhooks/{id}
  • PATCH /webhooks/{id}
  • DELETE /webhooks/{id}
  • POST /webhooks/{id}/rotate-secret
  • GET /webhooks/{id}/deliveries
  • POST /webhooks/{id}/deliveries/{deliveryId}/replay
Sandbox
  • Sandbox-Simulate header
  • Sandbox playground
  • Test data
Reference
  • Account tiers & trustScore
  • Settlement flow
  • SDKs
  • OpenAPI spec
  • Changelog
DocsCoreVersioning
Core

Versioning

Date-based versioning with header pinning.

Backwards-incompatible changes ship under dated versions. Pin the version your integration was tested against; otherwise we serve the version captured on your account at the time of activation.

text
Key2Pay-Version: 2026-05-01
New optional fields and new endpoints are not breaking changes and may be added between versions.
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Errors