APIparametrien

APIparametrien are values supplied with an API request that influence the operation performed by the API or the shape of the response. They are part of the contract between client and server and can be transmitted in multiple locations within the HTTP request.

Path parameters identify specific resources and are typically required, appearing in the URL path (for example, /users/{id}). Query parameters control filtering, paging, sorting, and optional modifiers (for example, ?page=2&limit=50&status=active). Header parameters convey metadata such as authentication information and content negotiation (for example, Authorization: Bearer token, Accept: application/json). Body parameters carry data for creation or updates and are common in POST, PUT, or PATCH requests.

APIs define parameter types (string, integer, boolean, array), constraints (required versus optional, min/max, allowed values), and defaults. Validation occurs on the server side, and errors are typically returned as 400 Bad Request or 422 Unprocessable Entity with details aboutInvalid parameters.

Security and best practices include avoiding placing sensitive information in query strings; prefer headers or body for sensitive data and ensure transmission over HTTPS. Parameter names should be stable, well documented, and versioned to support evolution. Use standard formats and encoding, and document the expected locations, requiredness, and examples. Common definition formats for describing parameters include OpenAPI, RAML, and API Blueprint.

Understanding parameter semantics helps with backward compatibility and client tooling. As APIs evolve, strategies such as deprecation notices and versioning help minimize breaking changes for clients.