Question 1

How does the Mock GraphQL Response Generator work?

Accepted Answer

Paste a GraphQL SDL schema (type User { id: ID! name: String! ... }, unions, interfaces, enums, custom scalars) and optionally a query (mutation/subscription). The tool parses the SDL into an in-memory type map, walks the query selection set, and produces a realistic mock JSON response shaped exactly to the query — with type-aware Faker values (emails, URLs, UUIDs, dates, numbers, etc.), configurable list sizes, custom per-field overrides, and __typename resolution for unions and interfaces.

Question 2

Which GraphQL features are supported?

Accepted Answer

SDL: type, interface, union, enum, input, scalar, custom scalars, field arguments, list types ([Type!]!), non-null modifiers (!). Query: Query/Mutation/Subscription operations, field selections, nested objects, fragments (inline + named), aliases, list fields with custom sizes, __typename. Recursion is capped at a configurable depth (default 3) to prevent infinite loops on self-referential types like User.friends: [User!]!.

Question 3

Can I override the mock value for specific fields?

Accepted Answer

Yes. The per-field overrides panel lets you set a literal value or a Faker-style template ({{name.firstName}}, {{internet.email}}, {{datatype.uuid}}, etc.) for any field path. Overrides take precedence over the type-aware default. Common custom scalars (Date, Email, URL, UUID, DateTime, JSON, BigInt, Decimal) are auto-mapped to realistic Faker values.

Question 4

Are my schemas or queries uploaded anywhere?

Accepted Answer

No. SDL parsing and mock generation run entirely in your browser. Nothing is sent to a server. History (last 20 generations) is stored in localStorage on this device only — metadata only, never the schema or query text — and the shareable URL encodes options in the fragment (after #) which browsers never transmit.

Question 5

What extras does this tool offer versus @graphql-tools/mock and Apollo mocking?

Accepted Answer

(1) Pure browser tool — no code or server required. (2) SDL parser supporting type/interface/union/enum/input/scalar/custom-scalar with non-null & list modifiers. (3) Query parser supporting selection sets, nested fields, fragments (inline + named), aliases, and __typename. (4) Type-aware Faker mapping for 12+ built-in + custom scalars. (5) Configurable list sizes (default, per-field override). (6) Recursion depth cap (default 3) with smart cycle-break. (7) Per-field overrides (literal or Faker template). (8) Nullable/error-state injection (random nulls, partial errors, full errors). (9) Seedable mulberry32 PRNG for reproducibility. (10) Union/interface __typename resolution. (11) MSW handler snippet export. (12) Apollo mock resolver snippet export. (13) Multiple operation detection (queries, mutations, subscriptions). (14) JSON / GraphQL-response / MSW / Apollo export formats. (15) localStorage history (max 20). (16) Shareable-URL config. (17) Copy / download. (18) Live preview with syntax highlighting.

Mock GraphQL Response Generator

Mock options

Mock result for query GetUser

Output (1,775 bytes)

How to use

Mock options

Mock result for query GetUser

Output (1,775 bytes)