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Introduction

Using the Closure Core API v3, integration partners — distributors, lead organizations, and vendors — can integrate Closure into their existing applications.

The current base URL of our API is:

Production: https://api.closure.nl
Staging: https://api.staging.closure.nl

All endpoints are documented in our API Reference.

Authentication​

Every request (except the anonymous health check) requires an X-Api-Key header. The API key identifies your organization and determines which routes and resources are accessible. Keys are issued per entity type:

  • Distributor keys grant access to heir, service request, document, and employee endpoints.
  • Lead organization keys grant access to the lead intake endpoint.
  • Vendor keys grant access to vendor user provisioning.

Invalid or missing keys return 401 with a Problem Details body (application/problem+json).

Rate limiting​

Rate limits apply per API key. When exceeded, the API returns 429 Too Many Requests. Treat it as retryable with backoff.

Versioning​

Changes on the API will be non-breaking for Version 3 (v3). Changes made to the API will therefore always be expansive, and can be found in the changelog within the documentation.