Do I need an API gateway for versioned APIs during a migration?

Not necessarily. An API gateway can help, but it’s not required just because you’re versioning APIs during a migration.

When you do not need a gateway

You can manage versioning without one if:

• The migration is simple, e.g. /v1 to /v2
• You can update clients in a controlled way
• Your backend can directly expose both versions
• Routing, auth, rate limiting, and logging are already handled elsewhere

When a gateway is useful

A gateway becomes helpful if you need to:

• Route traffic between old and new versions dynamically
• Support many clients with different rollout schedules
• Translate or transform requests/responses between versions
• Gradually shift traffic for canary or phased migration
• Centralize cross-cutting concerns like auth, throttling, observability, and policy enforcement

Common migration patterns

• Parallel versions: Keep /v1 and /v2 live at the same time
• Header-based versioning: Route based on Accept or custom headers
• Path-based versioning: Simple /api/v1/... and /api/v2/...
• Proxy/gateway-based routing: Useful when you want a single entry point to manage all of the above

Rule of thumb

• If you only need basic versioning, a gateway is optional.
• If you need traffic control, compatibility translation, or coordinated rollout, a gateway is often worth it.

If you want, I can help you decide based on your migration setup, like whether you’re doing path-based, header-based, or side-by-side API versions.