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swagger-api / swagger-codegen


swagger-codegen contains a template-driven engine to generate client code in different languages by parsing your Swagger Resource Declaration.


Swagger Code Generator

Build Status Maven Central


This is the swagger codegen project, which allows generation of client libraries automatically from a Swagger-compliant server.

Check out Swagger-Spec for additional information about the Swagger project, including additional libraries with support for other languages and more.

Table of contents


The Swagger Specification has undergone 3 revisions since initial creation in 2010. The swagger-codegen project has the following compatibilies with the swagger specification:

Swagger Codegen Version Release Date Swagger Spec compatibility Notes
2.1.5-SNAPSHOT 1.0, 1.1, 1.2, 2.0 master
2.1.4 (current stable) 2015-10-25 1.0, 1.1, 1.2, 2.0 tag v2.1.4
2.0.17 2014-08-22 1.1, 1.2 tag v2.0.17
1.0.4 2012-04-12 1.0, 1.1 tag v1.0.4


You need the following installed and available in your $PATH:

OS X Users

Don't forget to install Java 7. You probably have 1.6 or 1.8.

Export JAVA_HOME in order to use the supported Java version:

export JAVA_HOME=`/usr/libexec/java_home -v 1.7`
export PATH=${JAVA_HOME}/bin:$PATH


After cloning the project, you can build it from source with this command:

mvn package


Build and run using docker

git clone

cd swagger-codegen

./ mvn package

Build a Node.js server stub

./ generate \
  -i \
  -l nodejs \
  -o samples/server/petstore/nodejs


To install, run brew install swagger-codegen

Here is an example usage:

swagger-codegen generate -i -l ruby -o /tmp/test/

To generate a sample client library

You can build a client against the swagger sample petstore API as follows:


This will run the generator with this command:

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l java \
  -o samples/client/petstore/java

with a number of options. You can get the options with the help generate command:

        swagger generate - Generate code with chosen lang

        swagger generate [(-a <authorization> | --auth <authorization>)]
                [(-c <configuration file> | --config <configuration file>)]
                [-D <system properties>]
                (-i <spec file> | --input-spec <spec file>)
                (-l <language> | --lang <language>)
                [(-o <output directory> | --output <output directory>)]
                [(-t <template directory> | --template-dir <template directory>)]
                [(-v | --verbose)]
                [(-s | --skip-overwrite)]

        -a <authorization>, --auth <authorization>
            adds authorization headers when fetching the swagger definitions
            remotely. Pass in a URL-encoded string of name:header with a comma
            separating multiple values

        -c <configuration file>, --config <configuration file>
            Path to json configuration file. File content should be in a json
            format {"optionKey":"optionValue", "optionKey1":"optionValue1"...}
            Supported options can be different for each language. Run
            config-help -l {lang} command for language specific config options.

        -D <system properties>
            sets specified system properties in the format of

        -i <spec file>, --input-spec <spec file>
            location of the swagger spec, as URL or file (required)

        -l <language>, --lang <language>
            client language to generate (maybe class name in classpath,

        -o <output directory>, --output <output directory>
            where to write the generated files (current dir by default)

        -t <template directory>, --template-dir <template directory>
            folder containing the template files

        -v, --verbose
            verbose mode

        -s , --skip-overwrite
            specifies if the existing files should be overwritten during 
            the generation 

You can then compile and run the client, as well as unit tests against it:

cd samples/client/petstore/java
mvn package

Other languages have petstore samples, too:


Generating libraries from your server

It's just as easy--just use the -i flag to point to either a server or file.

Modifying the client library format

Don't like the default swagger client syntax? Want a different language supported? No problem! Swagger codegen processes mustache templates with the jmustache engine. You can modify our templates or make your own.

You can look at modules/swagger-codegen/src/main/resources/${your-language} for examples. To make your own templates, create your own files and use the -t flag to specify your template folder. It actually is that easy.

Making your own codegen modules

If you're starting a project with a new language and don't see what you need, swagger-codegen can help you create a project to generate your own libraries:

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar meta \
  -o output/myLibrary -n myClientCodegen -p

This will write, in the folder output/myLibrary, all the files you need to get started, including a Once modified and compiled, you can load your library with the codegen and generate clients with your own, custom-rolled logic.

Where is Javascript???

See our javascript library--it's completely dynamic and doesn't require static code generation. There is a third-party component called swagger-js-codegen that can generate angularjs or nodejs source code from a swagger specification.

Generating a client from local files

If you don't want to call your server, you can save the swagger spec files into a directory and pass an argument to the code generator like this:

-i ./modules/swagger-codegen/src/test/resources/2_0/petstore.json

Great for creating libraries on your ci server, from the Swagger Editor... or while coding on an airplane.

Selective generation

You may not want to generate all models in your project. Likewise you may want just one or two apis to be written. If that's the case, you can use system properties to control the output:

The default is generate everything supported by the specific library. Once you enable a feature, it will restrict the contents generated:

# generate only models
java -Dmodels {opts}

# generate only apis
java -Dapis {opts}

# generate only supporting files
java -DsupportingFiles

# generate models and supporting files
java -Dmodels -DsupportingFiles

To control the specific files being generated, you can pass a CSV list of what you want:

# generate the User and Pet models only

# generate the User model and the supportingFile ``:

When using selective generation, only the templates needed for the specific generation will be used.

Customizing the generator

There are different aspects of customizing the code generator beyond just creating or modifying templates. Each language has a supporting configuration file to handle different type mappings, etc:

$ ls -1 modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/

Each of these files creates reasonable defaults so you can get running quickly. But if you want to configure package names, prefixes, model folders, etc. you can use a json config file to pass the values.

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l java \
  -o samples/client/petstore/java \
  -c path/to/config.json

Supported config options can be different per language. Running config-help -l {lang} will show available options.

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar config-help -l java


        package for generated models

        package for generated api classes

        Sort method arguments to place required parameters before optional parameters. Default: true

        root package for generated code

        groupId in generated pom.xml

        artifactId in generated pom.xml

        artifact version in generated pom.xml

        source folder for generated code

        prefix for generated code members and local variables

        boolean - toggle "implements Serializable" for generated models

        library template (sub-template) to use:
        <default> - HTTP client: Jersey client 1.18. JSON processing: Jackson 2.4.2
        jersey2 - HTTP client: Jersey client 2.6
        okhttp-gson - HTTP client: OkHttp 2.4.0. JSON processing: Gson 2.3.1
        retrofit - HTTP client: OkHttp 2.4.0. JSON processing: Gson 2.3.1 (Retrofit 1.9.0)

Your config file for java can look like


For all the unspecified options default values will be used.

Another way to override default options is to extend the config class for the specific language. To change, for example, the prefix for the Objective-C generated files, simply subclass the

package com.mycompany.swagger.codegen;

import io.swagger.codegen.languages.*;

public class MyObjcCodegen extends ObjcClientCodegen {
  static {
    PREFIX = "HELO";

and specify the classname when running the generator:

-l com.mycompany.swagger.codegen.MyObjcCodegen

Your subclass will now be loaded and overrides the PREFIX value in the superclass.

Validating your swagger spec

You have options. The easiest is to use our online validator which not only will let you validate your spec, but with the debug flag, you can see what's wrong with your spec. For example:

Generating dynamic html api documentation

To do so, just use the -l dynamic-html flag when reading a spec file. This creates HTML documentation that is available as a single-page application with AJAX. To view the documentation:

cd samples/dynamic-html/
npm install
node .

Which launches a node.js server so the AJAX calls have a place to go.

Generating static html api documentation

To do so, just use the -l html flag when reading a spec file. This creates a single, simple HTML file with embedded css so you can ship it as an email attachment, or load it from your filesystem:

cd samples/html/
open index.html

To build a server stub

You can also use the codegen to generate a server for a couple different frameworks. Take a look here:


java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l nodejs \
  -o samples/server/petstore/nodejs

PHP Silex

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l silex \
  -o samples/server/petstore/silex

Ruby Sinatra

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l sinatra \
  -o samples/server/petstore/sinatra

Scala Scalatra

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l scalatra \
  -o samples/server/petstore/scalatra


java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l jaxrs \
  -o samples/server/petstore/jaxrs

Java Spring MVC

java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
  -i \
  -l spring-mvc \
  -o samples/server/petstore/spring-mvc

To build the codegen library

This will create the swagger-codegen library from source.

mvn package

Note! The templates are included in the library generated. If you want to modify the templates, you'll need to either repackage the library OR specify a path to your scripts

Online generators

One can also generate API client or server using the online generators (

For example, to generate Ruby API client, simply send the following HTTP request using curl:

curl -X POST -H "content-type:application/json" -d '{"swaggerUrl":""}'

Then you will receieve a JSON response with the URL to download the zipped code.

Guidelines for Contribution

Please refer to this page


Copyright 2015 SmartBear Software

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.