Convert Swagger 2.0 definitions to OpenApi 3.0.0 (and validate/lint)
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Convert Swagger 2.0 definitions into OpenApi 3.0.x

Currently tracking v3.0.0

If you are using Node.js 4 - please use the --harmony flag


swagger2openapi [options] [filename|url]
  --warnProperty    Property name to use for warning extensions
                                             [string] [default: "x-s2o-warning"]
  --version         Show version number                                [boolean]
  -c, --components  output information to unresolve a definition       [boolean]
  -d, --debug       enable debug mode, adds specification-extensions   [boolean]
  -e, --encoding    encoding for input/output files   [string] [default: "utf8"]
  -h, --help        Show help                                          [boolean]
  -i, --indent      JSON indent to use, defaults to 4 spaces            [string]
  -o, --outfile     the output file to write to                         [string]
  -p, --patch       fix up small errors in the source definition       [boolean]
  -r, --resolve     resolve external references                        [boolean]
  -u, --url         url of original spec, creates x-origin entry        [string]
  -v, --verbose     increase verbosity                                   [count]
  -w, --warnOnly    Do not throw on non-patchable errors, add warning extensions
  -y, --yaml        read and write YAML, default JSON                  [boolean]

or use the APIs:

var converter = require('swagger2openapi');
var options = {};
//options.patch = true; // fix up small errors in the source definition
//options.warnOnly = true; // Do not throw on non-patchable errors
converter.convertObj(swagger, options, function(err, options){
  // options.openapi contains the converted definition
// also available are asynchronous convertFile, convertUrl, convertStr and convertStream functions
// if you omit the callback parameter, you will instead receive a Promise
var validator = require('swagger2openapi/validate.js');
var options = {};
validator.validate(openapi, options, function(err, options){
  // options.valid contains the result of the validation
  // options.context now contains a stack (array) of JSON-Pointer strings
// also available is a synchronous validateSync method which returns a boolean

See here for complete documentation of the options object.

Or use the online version which also includes its own API.

Browser Support

See initial documentation.


OpenAPI 3.0.x validation

The testRunner harness can also be used as a simple validator if given one or more existing OpenAPI 3.x definitions. The validator (however it is called) uses WHATWG URL parsing if available (node 7.x and above). The testRunner can have a linting mode enabled with the --lint option. Rules are defined here. Contributions of rules and rule actions for the linter are very much appreciated.

Reference preservation

swagger2openapi preserves $ref JSON references in your API definition, and does not dereference every item, as with some model-based parsers.

Schema transformations

Swagger2openapi will automatically 'repair' a number of problems where non-compliant Swagger 2.0 schemas have been used. It will attempt to transform JSON schemas (used incorrectly) into OpenAPI 3.0.x Schema objects.

Specification extensions

swagger2openapi has support for a limited number of real-world specification extensions which have a direct bearing on the conversion. All other specification extensions are left untouched. swagger2openapi is swaggerplusplus-compatible.

It is expected to be able to configure the process of specification-extension modification using options or a plugin mechanism in a future release.


To run a test-suite:

node testRunner [-f {path-to-expected-failures}]... [{path-to-APIs|single-file...}]

The test harness currently expects files with a .json or .yaml extension, or a single named file, and has been tested on Node.js versions 4.x, 6.x and 8.x LTS (it is not recommended to run the test suite under Node.js version 7.x or Node.js versions less than 8.7.0 because of this bug) against

Additionally swagger2openapi has been tested on a corpus of 34,679 real-world valid Swagger 2.0 definitions from GitHub and SwaggerHub. However, if you have a definition which causes errors in the converter or does not pass validation, please do not hesitate to raise an issue.


BSD-3-Clause except the openapi-3.0.json schema, which is taken from the OpenAPI-Specification and the alternative gnostic-3.0.json schema, which is originally from Google Gnostic. Both of these are licensed under the Apache-2 license.