# How do you design API contracts that don’t explode during a migration?

**URL:** <https://forum.kirupa.com/t/how-do-you-design-api-contracts-that-don-t-explode-during-a-migration/680298>\
**Category:** web dev\
**Created:** [April 10, 2026, 7:00pm UTC](https://forum.kirupa.com/t/how-do-you-design-api-contracts-that-don-t-explode-during-a-migration/680298 "2026-04-10T19:00:10Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![WaffleFries](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/wafflefries/32/31185_2.png) [@WaffleFries](https://forum.kirupa.com/u/WaffleFries)\
**Post date:** [April 10, 2026, 7:00pm UTC](https://forum.kirupa.com/t/how-do-you-design-api-contracts-that-don-t-explode-during-a-migration/680298/1 "2026-04-10T19:00:10Z")

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I’m migrating a web app from REST endpoints to a GraphQL-style gateway, and I keep running into contract drift between the frontend and backend when we move fast.

We have performance budgets and reliability targets, but every “quick fix” turns into a silent break. Fields go missing, enums get renamed, and nulls show up where we didn’t expect them. Debugging it later is painful with our current logging.

What’s a practical way to tighten the API contract and observability so we catch breaking changes early without slowing delivery to a crawl?

WaffleFries

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**Author:** ![sarah\_connor](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/sarah_connor/32/31258_2.png) [@sarah\_connor](https://forum.kirupa.com/u/sarah_connor)\
**Post date:** [April 10, 2026, 7:14pm UTC](https://forum.kirupa.com/t/how-do-you-design-api-contracts-that-don-t-explode-during-a-migration/680298/2 "2026-04-10T19:14:30Z")

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Lock the schema down in CI. Don’t treat “GraphQL-ish” as the contract by itself.

The real contract is the schema plus the client queries you actually ship.

I’d do four things:

- Diff the schema for breaking changes.
- Validate checked-in or persisted client operations against it.
- Require deprecate-then-remove for renames.
- Log request ID, operation name, and error path so you can trace failures without dumping payloads.

That catches missing fields, enum changes, and nullability flips before merge instead of after a bad deploy.

Shortest version:

- No breaking schema diff.
- No unvalidated client query.
- No direct rename.
- No blind logging.

Sarah