Handling API Versioning

Choose a versioning strategy and document compatibility and retirement behavior. The examples separate the essential operation from the conditions a production implementation must enforce.

What It Does

Choose a versioning strategy and document compatibility and retirement behavior.

Prerequisites

Use a dedicated development environment with test accounts and records. Separate authorization, validation and error handling from response formatting; never copy demonstration-only secrets into production.

Example 1: Core Behavior

The first example isolates the core operation so its result is easy to understand.

<?php
$version='v1'; $allowed=['v1','v2'];
if (!in_array($version,$allowed,true)) { http_response_code(406); exit; }
echo $version;

Example 2: Alternative or Failure Case

The second example demonstrates an alternative outcome, rule or failure condition.

<?php
$major=2; $response=['apiVersion'=>$major,'data'=>['id'=>12]];
echo json_encode($response);

Practical Example: Applying the Rule

The practical example shows how to carry the same constraint into application code.

<?php
$accept='application/vnd.example.v2+json';
if (!preg_match('/v([12])\+json$/',$accept,$m)) { http_response_code(406); exit; }
echo 'Version '.$m[1];

Important Behavior and Edge Cases

Additive fields are usually safer than silently changing field types or semantics.

Comparison with Related Functions or Patterns

Common Beginner Mistakes

Key Takeaways

• Choose a versioning strategy and document compatibility and retirement behavior.
• Additive fields are usually safer than silently changing field types or semantics.
• Content negotiation can version representations without changing the resource URL.

Select this API or pattern based on its documented behavior and the trust boundaries in your own application, and test all external integrations against their actual deployments.