API Lifecycle Management Template

Overview

APIs are long-lived contracts between systems. Changing or removing an endpoint without a structured process breaks downstream consumers, causes outages, and damages trust. This template provides a checklist-driven approach for deprecating old versions, introducing new versions, and sunsetting APIs safely.

When to Use

Use this resource when:

• Planning to deprecate an API endpoint or version
• Introducing a breaking change that requires a new API version
• Preparing to shut down an entire API or service

Solution

# API Lifecycle Management: `<API Name>`

## 1. API Metadata

| Field | Value |
|-------|-------|
| API Name | `name` |
| Current Version | `v2.3` |
| Base URL | `https://api.example.com/v2` |
| Owner Team | `@platform-team` |
| Consumers | Internal: 3, External: 12 |

## 2. Deprecation Checklist

### 2.1. Decision & Communication

- [ ] Document the reason for deprecation (security, performance, maintainability)
- [ ] Identify all consumers using the deprecated endpoint/version
- [ ] Set a deprecation date (minimum 6 months for external APIs, 3 months for internal)
- [ ] Publish deprecation notice in:
  - [ ] API documentation (changelog)
  - [ ] Developer portal / status page
  - [ ] Direct email to registered consumers
  - [ ] Response headers (`Deprecation: true`, `Sunset: <date>`)

### 2.2. Migration Path

- [ ] Provide a migration guide with before/after examples
- [ ] Offer a sandbox environment for testing the new version
- [ ] Schedule office hours or Q&A sessions for consumer teams
- [ ] Create a compatibility shim if the migration is complex

### 2.3. Monitoring

- [ ] Track traffic to the deprecated endpoint daily
- [ ] Alert when usage drops below threshold (ready for shutdown)
- [ ] Maintain a dashboard of consumer migration progress

## 3. Versioning Checklist

### 3.1. Version Selection

- [ ] Determine if the change is backward-compatible (patch/minor) or breaking (major)
- [ ] Follow semantic versioning: `MAJOR.MINOR.PATCH`
- [ ] Update URL path (`/v3/`) or use header-based versioning (`Accept: application/vnd.api.v3+json`)

### 3.2. Release

- [ ] Deploy the new version alongside the old version
- [ ] Update documentation with new request/response examples
- [ ] Run contract tests against the new version
- [ ] Verify backward compatibility for non-breaking changes

### 3.3. Post-Release

- [ ] Monitor error rates and latency for the new version
- [ ] Collect feedback from early adopters
- [ ] Update SDKs and client libraries

## 4. Sunset Checklist

### 4.1. Pre-Shutdown

- [ ] Confirm zero traffic to the deprecated endpoint for 7 consecutive days
- [ ] Verify all known consumers have migrated (contact stragglers individually)
- [ ] Announce the final shutdown date (30 days notice)

### 4.2. Shutdown

- [ ] Disable the endpoint (return `410 Gone` or `404 Not Found`)
- [ ] Remove deprecated code and tests
- [ ] Update infrastructure (load balancer rules, DNS)
- [ ] Archive documentation with a redirect to the new version

### 4.3. Post-Shutdown

- [ ] Monitor for unexpected 404s from unknown consumers
- [ ] Document lessons learned
- [ ] Update API lifecycle timeline

Explanation

The checklist enforces a minimum notice period that respects consumer timelines. External APIs need longer deprecation windows because you cannot control when consumers update. The Sunset header is machine-readable, allowing client libraries to warn developers automatically. Tracking traffic before shutdown prevents surprise breakages from forgotten internal integrations.

Variants

Context	Approach	Notes
Internal microservices	Shorter timelines, stricter enforcement	Teams can coordinate via shared Slack channel
Public SaaS API	Long timelines, legal review	May require SLA commitments for deprecation notice
Mobile app backends	Force upgrade via app store	Use minimum app version checks to sunset old endpoints

Best Practices

1. Never remove an API without a deprecation period, even for internal use
2. Return deprecation headers as soon as the decision is made, not at shutdown
3. Maintain a public API changelog with dates for every change
4. Version the API contract independently of the service deployment
5. Keep deprecated endpoints observable with dedicated dashboards

Common Mistakes

1. Announcing deprecation but not tracking whether consumers actually migrate
2. Changing behavior on an existing version without bumping the version number
3. Removing documentation before the API is shut down
4. Assuming all consumers read email announcements
5. Forcing migrations during holiday seasons or fiscal quarter-ends

Frequently Asked Questions

How long should I keep a deprecated API alive?

External APIs: minimum 6-12 months. Internal APIs: minimum 3 months. Enterprise contracts may specify longer periods. Never deprecate during known high-traffic periods (Black Friday, tax season).

Should I use URL versioning or header versioning?

URL versioning (/v1/, /v2/) is explicit and easy to debug. Header versioning keeps URLs clean but is harder to cache and troubleshoot. Most teams use URL versioning for REST APIs.

What if a consumer refuses to migrate?

If a consumer is critical and cannot migrate in time, negotiate an extension with a hard deadline. If the consumer is non-critical, proceed with shutdown; the 410 Gone response will force action.