API Versioning Strategy Skill

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

Agent Skills: API Versioning Strategy

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