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Swagger Code Generator

Build Status Run Status Windows Test Maven Central PR Stats Issue Stats

⭐️⭐️⭐️ If you would like to contribute, please refer to guidelines and a list of open tasks.⭐️⭐️⭐️

📔 For more information, please refer to the Wiki page and FAQ 📔

⚠️ If the OpenAPI/Swagger spec is obtained from an untrusted source, please make sure you've reviewed the spec before using Swagger Codegen to generate the API client, server stub or documentation as code injection may occur ⚠️


This is the swagger codegen project, which allows generation of API client libraries, server stubs and documentation automatically given an OpenAPI Spec.

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

Swagger Codegen Version Release Date OpenAPI Spec compatibility Notes
2.3.0 (upcoming minor release) TBD 1.0, 1.1, 1.2, 2.0 Minor release with breaking changes
2.2.2 (upcoming patch release) TBD 1.0, 1.1, 1.2, 2.0 Patch release (without breaking changes)
2.2.1 (current stable) 2016-08-07 1.0, 1.1, 1.2, 2.0 tag v2.2.1
2.1.6 2016-04-06 1.0, 1.1, 1.2, 2.0 tag v2.1.6
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


If you're looking for the latest stable version, you can grab it directly from maven central (you'll need java 7 runtime at a minimum):

wget -O swagger-codegen-cli.jar

java -jar swagger-codegen-cli.jar help

On a mac, it's even easier with brew:

brew install swagger-codegen

To build from source, you need the following installed and available in your $PATH:

OS X Users

Don't forget to install Java 7 or 8. You probably have 1.6.

Export JAVA_HOME in order to use the supported Java version:

export JAVA_HOME=`/usr/libexec/java_home -v 1.8`
export PATH=${JAVA_HOME}/bin:$PATH


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

mvn clean package


Build and run using docker

git clone
cd swagger-codegen
./ mvn package

Run Docker in Vagrant

Prerequisite: install Vagrant and VirtualBox.

git clone
cd swagger-codegen
vagrant up
vagrant ssh
cd /vagrant
./ mvn package

Public Docker image


To install, run brew install swagger-codegen

Here is an example usage:

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

Getting Started

To generate a PHP client for, please run the following

git clone
cd swagger-codegen
mvn clean package
java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
   -i \
   -l php \
   -o /var/tmp/php_api_client

(if you're on Windows, replace the last command with java -jar modules\swagger-codegen-cli\target\swagger-codegen-cli.jar generate -i -l php -o c:\temp\php_api_client)

You can also download the JAR (latest release) directly from

To get a list of general options available, please run java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar help generate

To get a list of PHP specified options (which can be passed to the generator with a config file via the -c option), please run java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar config-help -l php


To generate a sample client library

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


(On Windows, run .\bin\windows\java-petstore.bat instead)

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-codegen-cli generate - Generate code with chosen lang

        swagger-codegen-cli generate
                [(-a <authorization> | --auth <authorization>)]
                [--additional-properties <additional properties>]
                [--api-package <api package>] [--artifact-id <artifact id>]
                [--artifact-version <artifact version>]
                [(-c <configuration file> | --config <configuration file>)]
                [-D <system properties>] [--group-id <group id>]
                (-i <spec file> | --input-spec <spec file>)
                [--import-mappings <import mappings>]
                [--instantiation-types <instantiation types>]
                [--invoker-package <invoker package>]
                (-l <language> | --lang <language>)
                [--language-specific-primitives <language specific primitives>]
                [--library <library>] [--model-package <model package>]
                [(-o <output directory> | --output <output directory>)]
                [(-s | --skip-overwrite)]
                [(-t <template directory> | --template-dir <template directory>)]
                [--type-mappings <type mappings>] [(-v | --verbose)]

        -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

        --additional-properties <additional properties>
            sets additional properties that can be referenced by the mustache
            templates in the format of name=value,name=value

        --api-package <api package>
            package for generated api classes

        --artifact-id <artifact id>
            artifactId in generated pom.xml

        --artifact-version <artifact version>
            artifact version in generated pom.xml

        -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

        --group-id <group id>
            groupId in generated pom.xml

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

        --import-mappings <import mappings>
            specifies mappings between a given class and the import that should
            be used for that class in the format of type=import,type=import

        --instantiation-types <instantiation types>
            sets instantiation type mappings in the format of
            type=instantiatedType,type=instantiatedType.For example (in Java):
            array=ArrayList,map=HashMap. In other words array types will get
            instantiated as ArrayList in generated code.

        --invoker-package <invoker package>
            root package for generated code

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

        --language-specific-primitives <language specific primitives>
            specifies additional language specific primitive types in the format
            of type1,type2,type3,type3. For example:

        --library <library>
            library template (sub-template)

        --model-package <model package>
            package for generated models

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

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

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

        --type-mappings <type mappings>
            sets mappings between swagger spec types and generated code types in
            the format of swaggerType=generatedType,swaggerType=generatedType.
            For example: array=List,map=Map,string=String

        -v, --verbose
            verbose mode

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.

You would then compile your library in the output/myLibrary folder with mvn package and execute the codegen like such:

java -cp output/myLibrary/target/myClientCodegen-swagger-codegen-1.0.0.jar:modules/swagger-codegen-cli/target/swagger-codegen-cli.jar io.swagger.codegen.SwaggerCodegen

Note the myClientCodegen is an option now, and you can use the usual arguments for generating your library:

java -cp output/myLibrary/target/myClientCodegen-swagger-codegen-1.0.0.jar:modules/swagger-codegen-cli/target/swagger-codegen-cli.jar \
  io.swagger.codegen.SwaggerCodegen generate -l myClientCodegen\
  -i \
  -o myClient

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 OpenAPI Specification.

❗️ On Dec 7th 2015, a Javascript API client generator has been added by @jfiala.

Generating a client from local files

If you don't want to call your server, you can save the OpenAPI 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 ``:

To control generation of docs and tests for api and models, pass false to the option. For api, these options are -DapiTests=false and -DapiDocs=false. For models, -DmodelTests=false and -DmodelDocs=false. These options default to true and don't limit the generation of the feature options listed above (like -Dapi):

# generate only models (with tests and documentation)
java -Dmodels {opts}

# generate only models (with tests but no documentation)
java -Dmodels -DmodelDocs=false {opts}

# generate only User and Pet models (no tests and no documentation)
java -Dmodels=User,Pet -DmodelTests=false {opts}

# generate only apis (without tests)
java -Dapis -DapiTests=false {opts}

# generate only apis (modelTests option is ignored)
java -Dapis -DmodelTests=false {opts}

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

Ignore file format

Swagger codegen supports a .swagger-codegen-ignore file, similar to .gitignore or .dockerignore you're probably already familiar with.

The ignore file allows for better control over overwriting existing files than the --skip-overwrite flag. With the ignore file, you can specify individual files or directories can be ignored. This can be useful, for example if you only want a subset of the generated code.


# Swagger Codegen Ignore
# Lines beginning with a # are comments

# This should match located anywhere.

# Matches in the root

# Exclude all recursively

# Explicitly allow files excluded by other rules

# Recursively exclude directories named Api
# You can't negate files below this directory.

# When this file is nested under /Api (excluded above),
# this rule is ignored because parent directory is excluded by previous rule.

# Exclude a single, nested file explicitly

The .swagger-codegen-ignore file must exist in the root of the output directory.

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

and config.json contains the following as an example:

  "apiPackage" : "petstore"

Supported config options can be different per language. Running config-help -l {lang} will show available options.
These options are applied via configuration file (e.g. config.json) or by passing them with `-D{optionName}={optionValue}. (If -D{optionName} does not work, please open a ticket and we'll look into it)

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
        feign - HTTP client: Netflix Feign 8.1.1.  JSON processing: Jackson 2.6.3
        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)
        retrofit2 - HTTP client: OkHttp 2.5.0. JSON processing: Gson 2.4 (Retrofit 2.0.0-beta2)

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.

Bringing your own models

Sometimes you don't want a model generated. In this case, you can simply specify an import mapping to tell the codegen what not to create. When doing this, every location that references a specific model will refer back to your classes. Note, this may not apply to all languages...

To specify an import mapping, use the --import-mappings argument and specify the model-to-import logic as such:

--import-mappings Pet=my.models.MyPet

Or for multiple mappings:


Validating your OpenAPI 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

Please refer to for more information.

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

Workflow integration

You can use the swagger-codegen-maven-plugin for integrating with your workflow, and generating any codegen target.

GitHub Integration

To push the auto-generated SDK to GitHub, we provide to streamline the process. For example:

1) Create a new repository in GitHub (Ref:

2) Generate the SDK

 java -jar modules/swagger-codegen-cli/target/swagger-codegen-cli.jar generate \
 -i modules/swagger-codegen/src/test/resources/2_0/petstore.json -l perl \
 --git-user-id "wing328" \
 --git-repo-id "petstore-perl" \
 --release-note "Github integration demo" \
 -o /var/tmp/perl/petstore

3) Push the SDK to GitHub

cd /var/tmp/perl/petstore
/bin/sh ./

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.

To customize the SDK, you can POST to{language} with the following HTTP body:

  "options": {},
  "swaggerUrl": ""

in which the options for a language can be obtained by submitting a GET request to{language}:

For example, curl returns

    "description":"python package name (convention: snake_case).",
    "description":"python package version.",
    "description":"Sort method arguments to place required parameters before optional parameters.",

To set package name to pet_store, the HTTP body of the request is as follows:

  "options": {
    "packageName": "pet_store"
  "swaggerUrl": ""

and here is the curl command:

curl -H "Content-type: application/json" -X POST -d '{"options": {"packageName": "pet_store"},"swaggerUrl": ""}'

Guidelines for Contribution

Please refer to this page

Companies/Projects using Swagger Codegen

Here are some companies/projects using Swagger Codegen in production. To add your company/project to the list, please visit and click on the icon to edit the page.

Swagger Codegen Core Team

Swagger Codegen core team members are contributors who have been making significant contributions (review issues, fix bugs, make enhancements, etc) to the project on a regular basis.

API Clients

Languages Core Team (join date)
C# @jimschubert (2016/05/01)
Clojure @xhh (2016/05/01)
Go @guohuang (2016/05/01) @neilotoole (2016/05/01)
Java @cbornet (2016/05/01) @xhh (2016/05/01) @epaul (2016/06/04)
Java (Spring Cloud) @cbornet (2016/07/19)
NodeJS/Javascript @xhh (2016/05/01)
ObjC @mateuszmackowiak (2016/05/09)
Perl @wing328 (2016/05/01)
PHP @arnested (2016/05/01)
Python @scottrw93 (2016/05/01)
Ruby @wing328 (2016/05/01) @zlx (2016/05/22)
Swift @jaz-ah (2016/05/01) @Edubits (2016/05/01)
TypeScript (Node) @Vrolijkx (2016/05/01)
TypeScript (Angular1) @Vrolijkx (2016/05/01)
TypeScript (Angular2) @Vrolijkx (2016/05/01)
TypeScript (Fetch)

Server Stubs

Languages Core Team (date joined)
C# ASP.NET5 @jimschubert (2016/05/01)
Go Server @guohuang (2016/06/13)
Haskell Servant
Java Spring Boot @cbornet (2016/07/19)
Java Spring MVC @kolyjjj (2016/05/01) @cbornet (2016/07/19)
NodeJS @kolyjjj (2016/05/01)
PHP Lumen @abcsum (2016/05/01)
PHP Silex
PHP Slim
Python Flask
Ruby Sinatra @wing328 (2016/05/01)
Scala Scalatra

Template Creator

Here is a list of template creators:

  • API Clients:
    • Akka-Scala: @cchafer
    • C++ REST: @Danielku15
    • C# (.NET 2.0): @who
    • Clojure: @xhh
    • Dart: @yissachar
    • Groovy: @victorgit
    • Go: @wing328
    • Java (Retrofit): @0legg
    • Java (Retrofi2): @emilianobonassi
    • Java (Jersey2): @xhh
    • Java (okhttp-gson): @xhh
    • Javascript/NodeJS: @jfiala
    • Javascript (Closure-annotated Angular) @achew22
    • Perl: @wing328
    • Swift: @tkqubo
    • Swift 3: @hexelon
    • TypeScript (Node): @mhardorf
    • TypeScript (Angular1): @mhardorf
    • TypeScript (Fetch): @leonyu
    • TypeScript (Angular2): @roni-frantchi
  • Server Stubs
    • C# ASP.NET5: @jimschubert
    • C# NancyFX: @mstefaniuk
    • Erlang Server: @galaxie
    • Go Server: @guohuang
    • Haskell Servant: @algas
    • Java MSF4J: @sanjeewa-malalgoda
    • Java Spring Boot: @diyfr
    • Java Undertow: @stevehu
    • JAX-RS RestEasy: @chameleon82
    • JAX-RS CXF: @hiveship
    • JAX-RS CXF (CDI): @nickcmaynard
    • PHP Lumen: @abcsum
    • PHP Slim: @jfastnacht
    • Ruby on Rails 5: @zlx
  • Documentation
    • HTML Doc 2: @jhitchcock
    • Confluence Wiki: @jhitchcock

How to join the core team

Here are the requirements to become a core team member:

  • rank within top 50 in
  • regular contributions to the project

    • about 3 hours per week
    • for contribution, it can be addressing issues, reviewing PRs submitted by others, submitting PR to fix bugs or make enhancements, etc

    To join the core team, please reach out to (@wing328) for more information.

    To become a Template Creator, simply submit a PR for new API client (e.g. Rust, Elixir) or server stub (e.g. Ruby Grape) generator.


Copyright 2016 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.