OpenAPI to GraphQL Schema Converter

Transpile OpenAPI and Swagger REST API definitions into clean GraphQL Query, Mutation, and type schemas in your browser.

At a glance

OpenAPI to GraphQL Schema Converter transforms OpenAPI 3.0, 3.1, and Swagger specifications into valid GraphQL SDL schemas. It maps GET endpoints to Query operations, POST/PUT/DELETE to Mutation operations, and components.schemas into strongly typed GraphQL types and inputs in browser memory.

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100% Client-Side In-Browser OpenAPI to GraphQL Transpiler

Compile REST OpenAPI 3.0, 3.1, and Swagger 2.0 definitions directly into GraphQL SDL Queries, Mutations, Types, and Inputs with zero server uploads.

Pure In-Browser
Presets:
Valid Spec 0 chars
Generation Options
0 chars
0 operations
GraphQL SDL Topology:
Queries 0
Mutations 0
Object Types 0
Inputs / Enums 0

Why Use This OpenAPI to GraphQL Schema Converter?

100% Client-Side Privacy: Your OpenAPI and Swagger specifications never leave your device or touch any external server.
Universal OpenAPI & Swagger Support: Transpiles OpenAPI 3.0.x, 3.1.x, and legacy Swagger 2.0 specs seamlessly.
Dual JSON and YAML Ingestion: Zero-dependency parser ingests formatted or minified JSON and YAML effortlessly.
Full Operations Mapping: Automatically generates Query fields from GET requests and Mutation fields from POST/PUT/PATCH/DELETE endpoints.
Strongly Typed SDL: Preserves non-null assertions (!), list types, enums, path/query arguments, and request bodies.

How to Use OpenAPI to GraphQL Schema Converter

1

Input OpenAPI or Swagger Spec

Paste your OpenAPI 3.0, 3.1, or Swagger 2.0 specification in JSON or YAML format into the input editor, or select a preset.

2

Configure Generation Options

Toggle Mutation generation, strict nullability (!) for required fields, and indentation formatting.

3

Copy or Download GraphQL SDL

Copy the generated GraphQL SDL to your clipboard with one click, or download it as a .graphql schema file.

OpenAPI 3.0 to GraphQL Schema example

Demonstrates converting an OpenAPI 3.0 specification with a GET /pets endpoint and Pet schema into GraphQL SDL Query and type declarations.

OpenAPI 3.0 JSON Specification Source 
{"openapi":"3.0.0","info":{"title":"Pet API","version":"1.0"},"paths":{"/pets":{"get":{"operationId":"getPets","responses":{"200":{"content":{"application/json":{"schema":{"type":"array","items":{"$ref":"#/components/schemas/Pet"}}}}}}}}},"components":{"schemas":{"Pet":{"type":"object","properties":{"id":{"type":"string"},"name":{"type":"string"}},"required":["id","name"]}}}}
Generated GraphQL SDL Schema Processed 
type Query {
  getPets: [Pet]
}

schema {
  query: Query
}

type Pet {
  id: String!
  name: String!
}

Technical Specifications & Engine Details

Technical specifications and engine details for OpenAPI to GraphQL Schema Converter
Specification Details
Supported Formats APPLICATION/JSON, APPLICATION/YAML, TEXT/YAML, TEXT/PLAIN, .JSON, .YAML, .YML → TEXT/PLAIN, APPLICATION/GRAPHQL, .GRAPHQL, .GQL
Execution Mode 100% Client-Side In-Browser (client)
Browser Requirements Modern browser with JavaScript enabled.
Performance Constraints Runs client-side in browser memory. Performance and file limits are bounded by available local device RAM.
Maintained by Pragyan Pahadi

100% Client-Side Privacy Guarantee

Your API specifications remain strictly on your local device. Zero data is transmitted to external servers.

Frequently Asked Questions

How does this tool map HTTP methods to GraphQL operations?
HTTP GET endpoints map to GraphQL Query fields, while POST, PUT, PATCH, and DELETE endpoints map to GraphQL Mutation fields. Operation names are derived from operationId or generated cleanly from the HTTP method and path.
Are path and query parameters supported in the generated GraphQL schema?
Yes. Path and query parameters are mapped to GraphQL field arguments with matching types (e.g., id: String!). Path parameters and required query parameters are marked non-null with exclamation marks (!).
How are request bodies handled in Mutations?
Request bodies from OpenAPI 3.x and Swagger 2.0 are mapped to input arguments (e.g., input: PetInput!). Input types are generated with appropriate field types matching the input schema.
Is my OpenAPI specification uploaded to any server?
No. The entire conversion process occurs 100% locally in your browser memory using client-side JavaScript. No data is ever transmitted over the network.

Methodology

This tool runs entirely in your browser. The example above shows a representative input and the result it produces.

Last updated .

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