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Mock GraphQL Error Generator
Used by developers, writers, and creators worldwide.
A mock GraphQL error generator helps frontend and backend developers build robust error handling without waiting for real server failures. GraphQL errors follow a specific structure — with message, locations, path, and extensions fields — and testing your UI against every error type is critical before shipping. This generator produces spec-compliant GraphQL error response payloads covering validation failures, authentication errors, not-found responses, and rate limiting. Choose a specific error category like Authentication or RateLimit, set the count up to however many parallel errors you need, and get a copy-paste-ready payload in seconds. Use it to drive Apollo Client error states, test React error boundaries, or populate Storybook stories for your error UI components without spinning up a real failing server.
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How to use
- Choose your options above
- Click Generate
- Copy your result
Use Cases
- •Testing Apollo Client error-handling logic in Jest with realistic UNAUTHENTICATED payloads
- •Populating Storybook stories for error state UI components across all four error categories
- •Simulating concurrent validation errors in Cypress end-to-end tests for form-heavy GraphQL mutations
- •Documenting expected error shapes in Postman collections or Notion API references for frontend teams
- •Reproducing RateLimit error responses locally when a third-party GraphQL API cap is hard to trigger
FAQ
what does a graphql error response payload actually look like
A GraphQL error response returns HTTP 200 with a JSON body containing a null or partial data field and an errors array. Each error object includes message, locations, path, and an extensions field that typically carries a machine-readable code like BAD_USER_INPUT or UNAUTHENTICATED.
why does graphql return 200 ok even when there's an error
GraphQL treats HTTP as a transport layer, not a semantic one — so it always returns 200 and encodes error details in the response body's errors array. This means your client code must check for errors in the JSON rather than relying on HTTP status codes, which is why mocking these payloads during testing is so important.
can i use these mock payloads with msw or apollo mocks in a react app
Yes. Copy the generated payload and return it from an MSW rest or graphql handler, or pass it directly to Apollo Client's MockedProvider as the result. This lets you test every error branch — validation, auth, rate limiting — without touching a real server.