API Versioning Migration Strategies
ExpertPlan and execute a migration from Data API v1 to v2 (or a future version) without breaking existing clients, using parallel routing, gradual rollout, and deprecation signals.
What you'll learn
- How to run v1 and v2 code paths in parallel during migration
- How to use deprecation headers to signal clients
- How to use feature flags to migrate a percentage of traffic
- How to verify v2 parity before retiring v1
Migrating an integration from one API version to another while keeping existing clients working requires a strategy beyond "update the URL." Parallel routing, feature flags, and deprecation headers let you move clients incrementally without a coordinated cutover event.
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Parallel routing in your middleware
During migration, your middleware can route to v1 or v2 based on a request header or environment variable. This lets you test v2 with internal traffic before switching production clients.
const FM_VERSION = req.headers.get('x-fm-api-version') ?? process.env.FM_API_VERSION ?? 'v1';
const base = `${FM_HOST}/fmi/data/${FM_VERSION}/databases/${DB}`;
// Internal test clients send: x-fm-api-version: v2
// Production clients use default (v1) until migration is completeSign in to track your progress and pick up where you left off.
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