OpenAPI Support

Stability: alpha

Reitit can generate OpenAPI 3.1.0 documentation. The feature works similarly to Swagger documentation.

The ring-malli-swagger and ring-spec-swagger examples also have OpenAPI documentation.

OpenAPI data

The following route data keys contribute to the generated swagger specification:

key	description
:openapi	map of any openapi data. Can contain keys like :deprecated.
:no-doc	optional boolean to exclude endpoint from api docs
:tags	optional set of string or keyword tags for an endpoint api docs
:summary	optional short string summary of an endpoint
:description	optional long description of an endpoint. Supports http://spec.commonmark.org/
:openapi/request-content-types	See the Per-content-type-coercions section below.
:openapi/response-content-types	See the Per-content-type-coercions section below. vector of supported response content types. Defaults to ["application/json"]. Only needed if you use the [:response nnn :content :default] coercion.

Coercion keys also contribute to the docs:

key	description
:parameters	optional input parameters for a route, in a format defined by the coercion
:request	optional description of body parameters, possibly per content-type
:responses	optional descriptions of responses, in a format defined by coercion

Annotating schemas

You can use malli properties, schema-tools data or spec-tools data to annotate your models with examples, descriptions and defaults that show up in the OpenAPI spec.

Malli:

["/plus"
 {:post
  {:parameters
   {:body [:map
           [:x
            {:title "X parameter"
             :description "Description for X parameter"
             :json-schema/default 42}
            int?]
           [:y int?]]}}}]

Schema:

["/plus"
 {:post
  {:parameters
   {:body {:x (schema-tools.core/schema s/Num {:description "Description for X parameter"
                                               :openapi/example 13
                                               :openapi/default 42})
           :y int?}}}}]

Spec:

["/plus"
 {:post
  {:parameters
   {:body (spec-tools.data-spec/spec ::foo
                                     {:x (schema-tools.core/spec {:spec int?
                                                                  :description "Description for X parameter"
                                                                  :openapi/example 13
                                                                  :openapi/default 42})
                                      :y int?}}}}}]

Per-content-type coercions

Use :request coercion (instead of :body) to unlock per-content-type coercions. This also lets you specify multiple named examples. See Coercion for more info. See also the openapi example.

["/pizza"
 {:get {:summary "Fetch a pizza | Multiple content-types, multiple examples"
        :responses {200 {:content {"application/json" {:description "Fetch a pizza as json"
                                                       :schema [:map
                                                                [:color :keyword]
                                                                [:pineapple :boolean]]
                                                       :examples {:white {:description "White pizza with pineapple"
                                                                          :value {:color :white
                                                                                  :pineapple true}}
                                                                  :red {:description "Red pizza"
                                                                        :value {:color :red
                                                                                :pineapple false}}}}
                                   "application/edn" {:description "Fetch a pizza as edn"
                                                      :schema [:map
                                                               [:color :keyword]
                                                               [:pineapple :boolean]]
                                                      :examples {:red {:description "Red pizza with pineapple"
                                                                       :value (pr-str {:color :red :pineapple true})}}}}}}

The special :default content types map to the content types supported by the Muuntaja instance. You can override these by using the :openapi/request-content-types and :openapi/response-content-types keys, which must contain vector of supported content types. If there is no Muuntaja instance, and these keys are not defined, the content types will default to ["application/json"].

Custom OpenAPI data

The :openapi route data key can be used to add top-level or route-level information to the generated OpenAPI spec. This is useful for providing "securitySchemes" or other OpenAPI keys that are not generated automatically by reitit.

See the openapi example for a working example of "securitySchemes".

OpenAPI spec

Serving the OpenAPI specification is handled by reitit.openapi/create-openapi-handler. It takes no arguments and returns a ring handler which collects at request-time data from all routes and returns an OpenAPI specification as Clojure data, to be encoded by a response formatter.

You can use the :openapi route data key of the create-openapi-handler route to populate the top level of the OpenAPI spec.

Example:

["/openapi.json"
 {:get {:handler (openapi/create-openapi-handler)
        :openapi {:info {:title "my nice api" :version "0.0.1"}}
        :no-doc true}}]

If you need to post-process the generated spec, just wrap the handler with a custom Middleware or an Interceptor.

Swagger-ui

Swagger-UI is a user interface to visualize and interact with the Swagger specification. To make things easy, there is a pre-integrated version of the swagger-ui as a separate module.

Note: you need Swagger-UI 5 for OpenAPI 3.1 support. As of 2023-03-10, a v5.0.0-alpha.0 is out.