Serve up Swagger UI and docs.
JavaScript CSS Ruby
Latest commit b395b12 Oct 30, 2014 @pasha pasha Merge pull request #16 from primedia/81704114_404s
Use new ?url= parameter to specify api-docs path


Serve up Swagger UI and docs.


Add this line to your application's Gemfile:

gem 'rack-swagger'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rack-swagger


Set up a docs folder in your project. Place the root API doc there and call it "swagger.json". Place your resource API docs there as well. For example, if you have one resource called "pet", your docs folder will have two files:

  • swagger.json (the root API doc)
  • pet.json (the pet resource)

In your, run, passing in the path to your docs folder.

run"../docs/", __FILE__))

This will serve the swagger-ui front-end at /docs/, and your doc files at /docs/api-docs/.

Your resource definitions should look ike this:

    "path": "/pet",
    "description": "Operations about pets"

Getting basePath right

Using overwrite_base_path

If you are seeing a lot of 404s or CORS-related errors in your docs, you may need to tweak the basePath.

You always need to have the basePath point to the same hostname as your API. If you have multiple deploys of your application under different hostnames, and they share the same set of JSON files, you can use the overwrite_base_path option in to vary this dynamically.

For example, say you have an environment variable called MY_API_HOST, which contains the hostname of your app for a given deployment:
    File.expand_path("../docs/", __FILE__),
    overwrite_base_path: ENV["MY_API_HOST"]
Setting basePath manually

If you're not using overwrite_base_path, rack-swagger will just use your basePath value from your JSON files. But just know that basePath will have different values depending on the file:

  • For the resource files, it should point to the API root path.
  • For the root file, it should point to the API root path, plus "/docs/api-docs".

Upgrading swagger-ui

A distribution of swagger-ui is included with rack-swagger. For developers who want to upgrade this distribution, there is a Rake task which pulls down the latest version and applies some changes to it. To use, run:

rake swagger_ui

If someone downloads the distribution without using the Rake task and you're trying to restore back to the original, remove the directory and version file before running the rake task:

rm -rf swagger-ui/
rm swagger_ui_version.yml
rake swagger_ui

Then check in the updated code.


For an example of properly formatted Swagger 1.2 JSON files working together with swagger-ui, see:


  1. Fork it ([my-github-username]/rack-swagger/fork )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request