CLI for turning APIs described by OpenAPI Specifications (OAS) into GraphQL interfaces

Usage no npm install needed!

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OpenAPI-to-GraphQL CLI

Command line interface (CLI) for turning APIs described by OpenAPI Specification (OAS) into GraphQL interfaces.

Overview of translation

Note: To use OpenAPI-to-GraphQL as a library, refer to the openapi-to-graphql package.


npm i -g openapi-to-graphql-cli


Usage: openapi-to-graphql <OAS JSON file path(s) and/or remote url(s)> [options]

  -V, --version                  output the version number
  -s, --strict                   throw an error if OpenAPI-to-GraphQL cannot run without compensating for errors or missing data in the OAS
  --save <file path>             save schema to path and do not start server

  -p, --port <port>              select the port where the server will start
  -u, --url <url>                select the base url which paths will be built on
  --cors                         enable Cross-origin resource sharing (CORS)

  -o, --operationIdFieldNames    create field names based on the operationId
  -f, --fillEmptyResponses       create placeholder schemas for operations with no response body rather than ignore them
  --addLimitArgument             add a limit argument on fields returning lists of objects/lists to control the data size
  --genericPayloadArgName        Sets argument name for the payload of a mutation to 'requestBody'
  --simpleNames                  Only remove illegal characters from names in the OAS and ignore casing and formatting
  --singularNames                Experimental feature that will create more meaningful names from the operation path

  -H, --header <key:value>       add headers to every request; repeatable flag; set using key:value notation (default: [])
  -Q, --queryString <key:value>  add query parameters to every request; repeatable flag; set using key:value notation (default: [])

  --no-viewer                    do not create GraphQL viewer objects for passing authentication credentials

  --no-extensions                do not add extentions, containing information about failed REST calls, to the GraphQL errors objects
  --no-equivalentToMessages      do not append information about the underlying REST operations to the description of fields
  -h, --help                     output usage information

The basic usage of the CLI takes the specified OAS, creates a GraphQL interface for it, and starts a server to host the GraphQL interface.

openapi-to-graphql oas.json

You can also create a GraphQL interface using multiple OASs.

openapi-to-graphql oas.json oas2.json oas3.json

You can specify the OAS by pointing to either a local file or a remote url such as Additionally, you can specify a port number so you can have multiple GraphQL servers running on the same machine.

openapi-to-graphql -p 3001

OpenAPI-to-GraphQL can also save a GraphQL schema to a local file, which you can use to inspect or change its content. Please note that the following command will not start the GraphQL server.

openapi-to-graphql oas.json --save schema.graphql

You can use multiple header and queryString to add headers and query strings to the resolvers. Use the syntax: {key}:{value}.

openapi-to-graphql oas.json -H someHeader:someValue -H anotherHeader:anotherValue -Q "exampleQueryString:This one contains spaces!"

To learn more about the other options, please refer here.

Please note that the CLI tool is mainly used for quick testing and does not offer all the features that createGraphQLSchema(oas, options) does.