Got Swag? A tool to test Swagger-powered APIs automatically

Usage no npm install needed!

<script type="module">
  import gotSwag from '';


Got Swag?

A tool to test Swagger-powered APIs automatically through monkey testing. Also allows for custom tests written directly in Swagger files or in separate test suites. Includes command-line and programmatic interfaces. Install via npm install got-swag -g.


got-swag <url> ... [-m] [-t <ms>] [-T] [-v] [-w]
  Test a Swagger URL or file (YAML). Additional files are merged.

  -m, --monkey        Run monkey tests on GET endpoints
  -l, --monkey-limit  Maximum number of parameter combinations for each
                      monkey GET, default is 50
  -t, --timeout <ms>  Set a timeout (in milliseconds) for test step execution,
                      default is 2000 ms
  -T, --trace         Trace: Log requests and responses
  -V, --version       Show version
  -w, --watch         Watch the Swagger files and rerun tests on changes

Most Mocha options are valid. See for details.

Monkey Testing

The most basic usage of got-swag is monkey testing: Each GET endpoint of a service is validated using minimal variable input, if any, and the definitions from the services' Swagger file. The endpoints are requested with random authentication/variable combinations until one combination leads to a response status code less than 400.

Just invoke got-swag on a URL with the -m switch:

got-swag -m

See monkeystore.yaml for an example of input variables.

Custom Tests

Additionally, got-swag allows to embed custom tests in Swagger files or separate test suites. The test steps are written in JS using a small domain-specific language. Every step is evaluated, even if a previous step failed.

For example, see petstore.yaml (embedded) and yoda.yaml (separate).

Test Syntax Reference


  • ok( actual )
  • equal( actual, expected )
  • notEqual( actual, expected )
  • deepEqual( actual, expected )
  • notDeepEqual( actual, expected )
  • strictEqual( actual, expected )
  • notStrictEqual( actual, expected )
  • deepStrictEqual( actual, expected )
  • notDeepStrictEqual( actual, expected )
  • match( actualString, expectedPattern )


  • validate( data, schema )
    • Validate JSON data against a JSON schema
    • If data or schema are omitted (strictly equal to undefined), the last response is validated against the current operation's response schema


  • request( options )
    • Requests the current endpoint
    • options is optional, see http
    • sets the request body
  • Shortcuts:
    • get( url, headers )
    • post( url, data, headers )
    • put( url, data, headers )
    • delete( url, headers )
    • options( url, headers )
    • head( url, headers )
    • Use null for url to request the current endpoint
    • headers are optional


  • auth( securityDefinitionId, credentials, scopes )
    • Authenticates against a security definition
    • scopes are optional and inferred from the API if possible


  • encodeURIComponent( s ) encodes a string for URI transmission
  • log( value ) logs a value
  • stringify( value ) alias of JSON.stringify
  • parse( string ) alias of JSON.parse
  • byteLength( string ) alias of Buffer.byteLength for computing 'Content-Length' header manually
  • monkeyAuth() tries to authenticate using known method/credentials
  • monkeyGet() tries to GET using known parameters


  • vars: Variables reusable for all tests
    • You can write to vars in test steps, see example
  • req: Last request data
  • res: Last response data
    • res.statusCode: Integer response status code
    • res.headers: Response headers
    • res.body: String response body
    • res.json: Parsed JSON response, if any
  • api: Complete Swagger API

Extension Syntax

You can define extension Swagger files on top of existing Swagger files using the '#/path': value syntax. For reference, see extended-petstore.yaml.

Programmatic Usage

var gotSwag = require( 'got-swag' );

// test api and report as JSON
gotSwag.test( 'swag.yaml', 'vars.yaml' ).then( function ( report ) {
  console.log( report );
} );

// describe mocha tests in current suite
describe( 'My test suite', function () {
  gotSwag.describe( 'swag.yaml', 'vars.yaml', { parent: this } );
} );


  • Currently, got-swag only supports JSON
  • The DSL is sandboxed using vm
  • If you see something like .../node_modules/got-swag/lib/validate.js:24 throw new Error( result.errors ); in your console, it's a Node.js Bug