api-versioning-strategy

name	api-versioning-strategy
description	Implements API versioning using URL paths, headers, or query parameters with backward compatibility and deprecation strategies. Use when managing multiple API versions, planning breaking changes, or designing migration paths.
license	MIT

API Versioning Strategy

Choose and implement API versioning approaches with proper deprecation timelines.

Versioning Methods

Method	Example	Pros	Cons
URL Path	/api/v1/users	Clear, cache-friendly	URL clutter
Header	API-Version: 1	Clean URLs	Hidden, harder to test
Query	?version=1	Easy to use	Not RESTful

URL Path Versioning (Recommended)

const v1Router = require('./routes/v1');
const v2Router = require('./routes/v2');

app.use('/api/v1', v1Router);
app.use('/api/v2', v2Router);

Version Adapter Pattern

// Transform between versions
const v1ToV2 = (v1Response) => ({
  data: {
    type: 'user',
    id: v1Response.user_id,
    attributes: {
      name: v1Response.user_name,
      email: v1Response.email
    }
  }
});

Deprecation Headers

app.use('/api/v1', (req, res, next) => {
  res.setHeader('Deprecation', 'true');
  res.setHeader('Sunset', 'Sat, 01 Jun 2025 00:00:00 GMT');
  res.setHeader('Link', '</api/v2>; rel="successor-version"');
  next();
});

Safe vs Breaking Changes

Safe Changes (no version bump):

• Adding optional fields
• Adding new endpoints
• Adding optional parameters

Breaking Changes (requires new version):

• Removing fields
• Changing field types
• Restructuring responses
• Removing endpoints

Deprecation Timeline

Phase	Duration	Actions
Deprecated	3 months	Add headers, docs
Sunset Announced	3 months	Email users
Read-Only	1 month	Disable writes
Shutdown	-	Return 410 Gone

Best Practices

• Support N-1 versions minimum
• Provide 6+ months migration window
• Include migration guides with code examples
• Monitor version usage to inform deprecation