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OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)

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Quick Overview

OpenAPI Generator is an open-source tool that generates API client libraries, server stubs, documentation, and configuration automatically from OpenAPI (formerly known as Swagger) specifications. It supports over 50 programming languages and frameworks, making it a versatile solution for API development and integration.

Pros

  • Supports a wide range of programming languages and frameworks
  • Generates consistent and well-documented code across different platforms
  • Regularly updated to support the latest OpenAPI specifications
  • Highly customizable through templates and configuration options

Cons

  • Generated code may require manual tweaking for specific use cases
  • Learning curve for advanced customization and template creation
  • Some generated code may not follow best practices for certain languages
  • Large codebase can make it challenging to contribute or debug issues

Code Examples

  1. Generating a Python client:
openapi-generator generate -i petstore.yaml -g python -o ./python-client

This command generates a Python client based on the petstore.yaml OpenAPI specification.

  1. Generating a Java Spring server:
openapi-generator generate -i petstore.yaml -g spring -o ./spring-server

This command generates a Java Spring server based on the petstore.yaml OpenAPI specification.

  1. Generating TypeScript-Angular client:
openapi-generator generate -i petstore.yaml -g typescript-angular -o ./angular-client

This command generates a TypeScript-Angular client based on the petstore.yaml OpenAPI specification.

Getting Started

  1. Install OpenAPI Generator:

    npm install @openapitools/openapi-generator-cli -g

  2. Create an OpenAPI specification file (e.g., api.yaml).

  3. Generate code for your desired language/framework:

    openapi-generator generate -i api.yaml -g <language> -o ./output

  4. Navigate to the output directory and follow the generated README for further instructions on using the generated code.

Competitor Comparisons

swagger-api logo

swagger-codegen

16,884

swagger-codegen contains a template-driven engine to generate documentation, API clients and server stubs in different languages by parsing your OpenAPI / Swagger definition.

Pros of swagger-codegen

  • Longer history and established user base
  • Simpler architecture, potentially easier for beginners
  • Supports some legacy OpenAPI/Swagger versions

Cons of swagger-codegen

  • Less frequent updates and slower development cycle
  • Fewer supported languages and frameworks
  • Limited customization options compared to openapi-generator

Code Comparison

swagger-codegen:

public class SwaggerCodegen extends DefaultCodegen implements CodegenConfig {
    public SwaggerCodegen() {
        super();
        // Configuration setup
    }
}

openapi-generator:

public class OpenAPIGenerator extends DefaultCodegen implements CodegenConfig {
    public OpenAPIGenerator() {
        super();
        // More extensive configuration options
    }
}

The code structures are similar, but openapi-generator typically offers more configuration options and flexibility in its generator classes.

openapi-generator has evolved from swagger-codegen, offering improvements in various areas:

  1. More frequent updates and active community development
  2. Support for a wider range of programming languages and frameworks
  3. Enhanced customization options and template overrides
  4. Better handling of OpenAPI 3.x specifications
  5. Improved code quality and test coverage

While swagger-codegen remains a viable option, especially for projects with legacy Swagger specifications, openapi-generator is generally considered more feature-rich and actively maintained. The choice between the two depends on specific project requirements and preferences.

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Pros of API Blueprint

  • Simpler, more human-readable syntax using Markdown
  • Focuses on design-first approach, encouraging better API planning
  • Supports mock servers and documentation generation out-of-the-box

Cons of API Blueprint

  • Less widely adopted compared to OpenAPI Specification
  • Limited tooling ecosystem and community support
  • Lacks some advanced features available in OpenAPI, such as complex schema definitions

Code Comparison

API Blueprint:

# GET /users/{id}
+ Parameters
    + id: 1 (number, required) - User ID
+ Response 200 (application/json)
    + Attributes
        + name: John Doe (string)
        + email: john@example.com (string)

openapi-generator (OpenAPI 3.0):

/users/{id}:
  get:
    parameters:
      - name: id
        in: path
        required: true
        schema:
          type: integer
    responses:
      '200':
        content:
          application/json:
            schema:
              type: object
              properties:
                name:
                  type: string
                email:
                  type: string

While API Blueprint offers a more concise and readable syntax, openapi-generator (using OpenAPI Specification) provides a more structured and detailed approach. The OpenAPI ecosystem offers broader tool support and integration capabilities, making it more suitable for complex API projects. However, API Blueprint's simplicity can be advantageous for smaller projects or rapid prototyping.

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prism

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Turn any OpenAPI2/3 and Postman Collection file into an API server with mocking, transformations and validations.

Pros of Prism

  • Lightweight and focused on API mocking and validation
  • Faster setup and easier to use for simple API scenarios
  • Better suited for rapid prototyping and testing

Cons of Prism

  • Limited code generation capabilities compared to OpenAPI Generator
  • Less extensive language and framework support
  • Fewer customization options for complex API scenarios

Code Comparison

Prism (CLI usage):

prism mock api.yaml

OpenAPI Generator (CLI usage):

openapi-generator generate -i api.yaml -g java -o ./generated

Summary

Prism is a lightweight tool focused on API mocking and validation, making it ideal for rapid prototyping and simple API scenarios. It offers faster setup and easier usage compared to OpenAPI Generator.

OpenAPI Generator, on the other hand, provides more extensive code generation capabilities, supporting a wide range of programming languages and frameworks. It offers greater customization options for complex API scenarios but may require more setup time.

The choice between the two depends on the specific needs of your project. Prism is better suited for quick API mocking and validation, while OpenAPI Generator excels in generating comprehensive client libraries and server stubs across multiple languages and frameworks.

Redocly logo

redoc

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📘 OpenAPI/Swagger-generated API Reference Documentation

Pros of Redoc

  • Focused on API documentation rendering with a sleek, modern interface
  • Easier to set up and use for quick API documentation needs
  • Supports interactive "Try it out" feature for API endpoints

Cons of Redoc

  • Limited to API documentation generation only
  • Less customization options compared to openapi-generator
  • Doesn't support code generation for client libraries or server stubs

Code Comparison

Redoc (HTML embedding):

<script src="https://cdn.redoc.ly/redoc/latest/bundles/redoc.standalone.js"></script>
<redoc spec-url="https://api.example.com/openapi.json"></redoc>

openapi-generator (CLI usage):

openapi-generator generate -i https://api.example.com/openapi.json -g python -o ./generated

Summary

Redoc is a specialized tool for rendering OpenAPI documentation with a focus on user-friendly, interactive API reference pages. It's ideal for projects that need quick, attractive API documentation without extensive customization or code generation needs.

openapi-generator, on the other hand, is a more comprehensive tool that can generate client libraries, server stubs, and documentation in various formats and languages. It offers greater flexibility and customization options but may require more setup and configuration for simple documentation tasks.

Choose Redoc for straightforward, visually appealing API documentation, and openapi-generator for more complex API development workflows involving code generation and extensive customization.

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README

OpenAPI Generator

Stable releases in Maven Central Apache 2.0 License Open Collective backers Join the Slack chat room Follow OpenAPI Generator Twitter account to get the latest update Contribute with Gitpod Conan Center Revved up by Develocity

Master (7.9.0): Build Status Integration Test2 Windows Test Bitrise

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

:bangbang: To migrate from Swagger Codegen to OpenAPI Generator, please refer to the migration guide :bangbang:

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

:notebook_with_decorative_cover: The eBook A Beginner's Guide to Code Generation for REST APIs is a good starting point for beginners :notebook_with_decorative_cover:

:warning: If the OpenAPI spec, templates or any input (e.g. options, environment variables) is obtained from an untrusted source or environment, please make sure you've reviewed these inputs before using OpenAPI Generator to generate the API client, server stub or documentation to avoid potential security issues (e.g. code injection). For security vulnerabilities, please contact team@openapitools.org. :warning:

:bangbang: Both "OpenAPI Tools" (https://OpenAPITools.org - the parent organization of OpenAPI Generator) and "OpenAPI Generator" are not affiliated with OpenAPI Initiative (OAI) :bangbang:

Sponsors

If you find OpenAPI Generator useful for work, please consider asking your company to support this Open Source project by becoming a sponsor. You can also individually sponsor the project by becoming a backer.

Thank you to our bronze sponsors!

NamSor LightBow

Thank you GoDaddy for sponsoring the domain names, Linode for sponsoring the VPS, Checkly for sponsoring the API monitoring and Gradle for sponsoring Develocity

Linode

Overview

OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (both 2.0 and 3.0 are supported). Currently, the following languages/frameworks are supported:

Languages/Frameworks
API clientsActionScript, Ada, Apex, Bash, C, C# (.net 2.0, 3.5 or later, .NET Standard 1.3 - 2.1, .NET Core 3.1, .NET 5.0. Libraries: RestSharp, GenericHost, HttpClient), C++ (Arduino, cpp-restsdk, Qt5, Tizen, Unreal Engine 4), Clojure, Crystal, Dart, Elixir, Elm, Eiffel, Erlang, Go, Groovy, Haskell (http-client, Servant), Java (Apache HttpClient 4.x, Apache HttpClient 5.x, Jersey2.x, OkHttp, Retrofit1.x, Retrofit2.x, Feign, RestTemplate, RESTEasy, Vertx, Google API Client Library for Java, Rest-assured, Spring 5 Web Client, Spring 6 RestClient, MicroProfile Rest Client, Helidon), Jetbrains HTTP Client, Julia, k6, Kotlin, Lua, N4JS, Nim, Node.js/JavaScript (ES5, ES6, AngularJS with Google Closure Compiler annotations, Flow types, Apollo GraphQL DataStore), Objective-C, OCaml, Perl, PHP, PowerShell, Python, R, Ruby, Rust (hyper, reqwest, rust-server), Scala (akka, http4s, scalaz, sttp, swagger-async-httpclient, pekko), Swift (2.x, 3.x, 4.x, 5.x), Typescript (AngularJS, Angular (9.x - 18.x), Aurelia, Axios, Fetch, Inversify, jQuery, Nestjs, Node, redux-query, Rxjs), XoJo, Zapier
Server stubsAda, C# (ASP.NET Core, Azure Functions), C++ (Pistache, Restbed, Qt5 QHTTPEngine), Erlang, F# (Giraffe), Go (net/http, Gin, Echo), Haskell (Servant, Yesod), Java (MSF4J, Spring, Undertow, JAX-RS: CDI, CXF, Inflector, Jersey, RestEasy, Play Framework, PKMST, Vert.x, Apache Camel, Helidon), Julia, Kotlin (Spring Boot, Ktor, Vert.x), PHP (Flight, Laravel, Lumen, Mezzio (fka Zend Expressive), Slim, Silex, Symfony), Python (FastAPI, Flask), NodeJS, Ruby (Sinatra, Rails5), Rust (rust-server), Scala (Akka, Finch, Lagom, Play, Cask, Scalatra)
API documentation generatorsHTML, Confluence Wiki, Asciidoc, Markdown, PlantUML
Configuration filesApache2
OthersGraphQL, JMeter, Ktorm, MySQL Schema, Postman Collection, Protocol Buffer, WSDL

Table of contents

1 - Installation

1.1 - Compatibility

The OpenAPI Specification has undergone 3 revisions since initial creation in 2010. The openapi-generator project has the following compatibilities with the OpenAPI Specification:

OpenAPI Generator VersionRelease DateNotes
7.9.0 (upcoming minor release) SNAPSHOT23.09.2024Minor release with breaking changes (with fallback)
7.8.0 (latest stable release)19.08.2024Minor release with breaking changes (with fallback)
6.6.011.05.2023Minor release with breaking changes (with fallback)
5.4.031.01.2022Minor release with breaking changes (with fallback)
4.3.106.05.2020Patch release (enhancements, bug fixes, etc)

OpenAPI Spec compatibility: 1.0, 1.1, 1.2, 2.0, 3.0, 3.1 (beta support)

(We do not publish daily/nightly build. Please use SNAPSHOT instead)

For old releases, please refer to the Release page.

For decomissioned generators/libraries/frameworks, please refer to the "Decommission" label in the pull request page.

1.2 - Artifacts on Maven Central

You can find our released artifacts on maven central:

Core:

<dependency>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator</artifactId>
    <version>${openapi-generator-version}</version>
</dependency>

See the different versions of the openapi-generator artifact available on maven central.

Cli:

<dependency>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-cli</artifactId>
    <version>${openapi-generator-version}</version>
</dependency>

See the different versions of the openapi-generator-cli artifact available on maven central.

Maven plugin:

<dependency>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-maven-plugin</artifactId>
    <version>${openapi-generator-version}</version>
</dependency>

Gradle plugin:

<dependency>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-gradle-plugin</artifactId>
    <version>${openapi-generator-version}</version>
</dependency>

1.3 - Download JAR

If you're looking for the latest stable version, you can grab it directly from Maven.org (Java 11 runtime at a minimum):

JAR location: https://repo1.maven.org/maven2/org/openapitools/openapi-generator-cli/7.8.0/openapi-generator-cli-7.8.0.jar

For Mac/Linux users:

wget https://repo1.maven.org/maven2/org/openapitools/openapi-generator-cli/7.8.0/openapi-generator-cli-7.8.0.jar -O openapi-generator-cli.jar

For Windows users, you will need to install wget or you can use Invoke-WebRequest in PowerShell (3.0+), e.g.

Invoke-WebRequest -OutFile openapi-generator-cli.jar https://repo1.maven.org/maven2/org/openapitools/openapi-generator-cli/7.8.0/openapi-generator-cli-7.8.0.jar

After downloading the JAR, run java -jar openapi-generator-cli.jar help to show the usage.

For Mac users, please make sure Java 11 is installed (Tips: run java -version to check the version), and export JAVA_HOME in order to use the supported Java version:

export JAVA_HOME=`/usr/libexec/java_home -v 1.11`
export PATH=${JAVA_HOME}/bin:$PATH

Launcher Script

One downside to manual jar downloads is that you don't keep up-to-date with the latest released version. We have a Bash launcher script at bin/utils/openapi-generator.cli.sh which resolves this issue.

To install the launcher script, copy the contents of the script to a location on your path and make the script executable.

An example of setting this up (NOTE: Always evaluate scripts curled from external systems before executing them).

mkdir -p ~/bin/openapitools
curl https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/bin/utils/openapi-generator-cli.sh > ~/bin/openapitools/openapi-generator-cli
chmod u+x ~/bin/openapitools/openapi-generator-cli
export PATH=$PATH:~/bin/openapitools/

Now, openapi-generator-cli is "installed". On invocation, it will query the GitHub repository for the most recently released version. If this matches the last downloaded jar, it will execute as normal. If a newer version is found, the script will download the latest release and execute it.

If you need to invoke an older version of the generator, you can define the variable OPENAPI_GENERATOR_VERSION either ad hoc or globally. You can export this variable if you'd like to persist a specific release version.

Examples:

# Execute latest released openapi-generator-cli
openapi-generator-cli version

# Execute version 4.1.0 for the current invocation, regardless of the latest released version
OPENAPI_GENERATOR_VERSION=4.1.0 openapi-generator-cli version

# Execute version 4.1.0-SNAPSHOT for the current invocation
OPENAPI_GENERATOR_VERSION=4.1.0-SNAPSHOT openapi-generator-cli version

# Execute version 4.0.2 for every invocation in the current shell session
export OPENAPI_GENERATOR_VERSION=4.0.2
openapi-generator-cli version # is 4.0.2
openapi-generator-cli version # is also 4.0.2

# To "install" a specific version, set the variable in .bashrc/.bash_profile
echo "export OPENAPI_GENERATOR_VERSION=4.0.2" >> ~/.bashrc
source ~/.bashrc
openapi-generator-cli version # is always 4.0.2, unless any of the above overrides are done ad hoc

1.4 - Build Projects

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

After cloning the project, you can build it from source using maven wrapper:

  • Linux: ./mvnw clean install
  • Windows: mvnw.cmd clean install

Nix users

If you're a nix user, you can enter OpenAPI Generator shell, by typing:

nix develop

It will enter a shell with Java 11 installed.

Direnv supports automatically loading of the nix developer shell, so if you're using direnv too, type:

direnv allow

and have java and mvn set up with correct versions each time you enter project directory.

The default build contains minimal static analysis (via CheckStyle). To run your build with PMD and Spotbugs, use the static-analysis profile:

  • Linux: ./mvnw -Pstatic-analysis clean install
  • Windows: mvnw.cmd -Pstatic-analysis clean install

1.5 - Homebrew

To install, run brew install openapi-generator

Here is an example usage to generate a Ruby client:

openapi-generator generate -i https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml -g ruby -o /tmp/test/

To reinstall with the latest master, run brew uninstall openapi-generator && brew install --HEAD openapi-generator

To install OpenJDK (pre-requisites), please run

brew tap AdoptOpenJDK/openjdk
brew install --cask adoptopenjdk11
export JAVA_HOME=`/usr/libexec/java_home -v 1.11`

or download installer via https://adoptium.net/

To install Maven (optional), please run

brew install maven

1.6 - Docker

Public Pre-built Docker images

OpenAPI Generator CLI Docker Image

The OpenAPI Generator image acts as a standalone executable. It can be used as an alternative to installing via homebrew, or for developers who are unable to install Java or upgrade the installed version.

To generate code with this image, you'll need to mount a local location as a volume.

Example:

docker run --rm -v "${PWD}:/local" openapitools/openapi-generator-cli generate \
    -i https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml \
    -g go \
    -o /local/out/go

The generated code will be located under ./out/go in the current directory.

OpenAPI Generator Online Docker Image

The openapi-generator-online image can act as a self-hosted web application and API for generating code. This container can be incorporated into a CI pipeline, and requires at least two HTTP requests and some docker orchestration to access generated code.

Example usage:

# Start container at port 8888 and save the container id
> CID=$(docker run -d -p 8888:8080 openapitools/openapi-generator-online)

# allow for startup
> sleep 10

# Get the IP of the running container (optional)
GEN_IP=$(docker inspect --format '{{.NetworkSettings.IPAddress}}'  $CID)

# Execute an HTTP request to generate a Ruby client
> curl -X POST --header 'Content-Type: application/json' --header 'Accept: application/json' \
-d '{"openAPIUrl": "https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml"}' \
'http://localhost:8888/api/gen/clients/ruby'

{"code":"c2d483.3.4672-40e9-91df-b9ffd18d22b8","link":"http://localhost:8888/api/gen/download/c2d483.3.4672-40e9-91df-b9ffd18d22b8"}

# Download the generated zip file
> wget http://localhost:8888/api/gen/download/c2d483.3.4672-40e9-91df-b9ffd18d22b8

# Unzip the file
> unzip c2d483.3.4672-40e9-91df-b9ffd18d22b8

# Shutdown the openapi generator image
> docker stop $CID && docker rm $CID

Development in docker

You can use run-in-docker.sh to do all development. This script maps your local repository to /gen in the docker container. It also maps ~/.m2/repository to the appropriate container location.

To execute mvn package:

git clone https://github.com/openapitools/openapi-generator
cd openapi-generator
./run-in-docker.sh mvn package

Build artifacts are now accessible in your working directory.

Once built, run-in-docker.sh will act as an executable for openapi-generator-cli. To generate code, you'll need to output to a directory under /gen (e.g. /gen/out). For example:

./run-in-docker.sh help # Executes 'help' command for openapi-generator-cli
./run-in-docker.sh list # Executes 'list' command for openapi-generator-cli
./run-in-docker.sh generate -i modules/openapi-generator/src/test/resources/3_0/petstore.yaml \
    -g go -o /gen/out/go-petstore -p packageName=petstore # generates go client, outputs locally to ./out/go-petstore
Troubleshooting

If an error like this occurs, just execute the ./mvnw clean install -U command:

org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.19.1:test (default-test) on project openapi-generator: A type incompatibility occurred while executing org.apache.maven.plugins:maven-surefire-plugin:2.19.1:test: java.lang.ExceptionInInitializerError cannot be cast to java.io.IOException

./run-in-docker.sh ./mvnw clean install -U

Failed to execute goal org.fortasoft:gradle-maven-plugin:1.0.8:invoke (default) on project openapi-generator-gradle-plugin-mvn-wrapper: org.gradle.tooling.BuildException: Could not execute build using Gradle distribution 'https://services.gradle.org/distributions/gradle-4.7-bin.zip'

Right now: no solution for this one :|

Run Docker in Vagrant

Prerequisite: install Vagrant and VirtualBox.

git clone https://github.com/openapitools/openapi-generator.git
cd openapi-generator
vagrant up
vagrant ssh
cd /vagrant
./run-in-docker.sh ./mvnw package

1.7 - NPM

There is also an NPM package wrapper available for different platforms (e.g. Linux, Mac, Windows). (JVM is still required) Please see the project's README there for more information.

Install it globally to get the CLI available on the command line:

npm install @openapitools/openapi-generator-cli -g
openapi-generator-cli version

To use a specific version of "openapi-generator-cli"

openapi-generator-cli version-manager set 7.8.0

Or install it as dev-dependency:

npm install @openapitools/openapi-generator-cli -D

You can use locally built JARs or SNAPSHOT versions as well.

2 - Getting Started

To generate a PHP client for petstore.yaml, please run the following

git clone https://github.com/openapitools/openapi-generator
cd openapi-generator
./mvnw clean package
java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate \
   -i https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml \
   -g php \
   -o /var/tmp/php_api_client

(if you're on Windows, replace the last command with java -jar modules\openapi-generator-cli\target\openapi-generator-cli.jar generate -i https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml -g php -o c:\temp\php_api_client)

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

To get a list of general options available, please run java -jar modules/openapi-generator-cli/target/openapi-generator-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/openapi-generator-cli/target/openapi-generator-cli.jar config-help -g php

3 - Usage

To generate a sample client library

You can build a client against the Petstore API as follows:

./bin/generate-samples.sh ./bin/configs/java-okhttp-gson.yaml

(On Windows, please install GIT Bash for Windows to run the command above)

This script uses the default library, which is okhttp-gson. It will run the generator with this command:

java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate \
  -i https://raw.githubusercontent.com/openapitools/openapi-generator/master/modules/openapi-generator/src/test/resources/3_0/petstore.yaml \
  -g java \
  -t modules/openapi-generator/src/main/resources/Java \
  --additional-properties artifactId=petstore-okhttp-gson,hideGenerationTimestamp=true \
  -o samples/client/petstore/java/okhttp-gson

with a number of options. The java options are documented here.

You can also get the options with the help generate command (below only shows partial results):

NAME
        openapi-generator-cli generate - Generate code with the specified
        generator.

SYNOPSIS
        openapi-generator-cli generate
                [(-a <authorization> | --auth <authorization>)]
                [--api-name-suffix <api name suffix>] [--api-package <api package>]
                [--artifact-id <artifact id>] [--artifact-version <artifact version>]
                [(-c <configuration file> | --config <configuration file>)] [--dry-run]
                [(-e <templating engine> | --engine <templating engine>)]
                [--enable-post-process-file]
                [(-g <generator name> | --generator-name <generator name>)]
                [--generate-alias-as-model] [--git-host <git host>]
                [--git-repo-id <git repo id>] [--git-user-id <git user id>]
                [--global-property <global properties>...] [--group-id <group id>]
                [--http-user-agent <http user agent>]
                [(-i <spec file> | --input-spec <spec file>)]
                [--ignore-file-override <ignore file override location>]
                [--import-mappings <import mappings>...]
                [--instantiation-types <instantiation types>...]
                [--invoker-package <invoker package>]
                [--language-specific-primitives <language specific primitives>...]
                [--legacy-discriminator-behavior] [--library <library>]
                [--log-to-stderr] [--minimal-update]
                [--model-name-prefix <model name prefix>]
                [--model-name-suffix <model name suffix>]
                [--model-package <model package>]
                [(-o <output directory> | --output <output directory>)] [(-p <additional properties> | --additional-properties <additional properties>)...]
                [--package-name <package name>] [--release-note <release note>]
                [--remove-operation-id-prefix]
                [--reserved-words-mappings <reserved word mappings>...]
                [(-s | --skip-overwrite)] [--server-variables <server variables>...]
                [--skip-validate-spec] [--strict-spec <true/false strict behavior>]
                [(-t <template directory> | --template-dir <template directory>)]
                [--type-mappings <type mappings>...] [(-v | --verbose)]

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

...... (results omitted)

        -v, --verbose
            verbose mode

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

cd samples/client/petstore/java/okhttp-gson
mvn package

Other generators have samples too.

3.1 - Customization

Please refer to customization.md on how to customize the output (e.g. package name, version)

3.2 - Workflow Integration (Maven, Gradle, Github, CI/CD)

Please refer to integration.md on how to integrate OpenAPI generator with Maven, Gradle, sbt, Bazel, Github and CI/CD.

3.3 - Online OpenAPI generator

Here are the public online services:

The server is sponsored by Linode Linode Logo

(These services are beta and do not have any guarantee on service level)

Please refer to online.md on how to run and use the openapi-generator-online - a web service for openapi-generator.

3.4 - License information on Generated Code

The OpenAPI Generator project is intended as a benefit for users of the Open API Specification. The project itself has the License as specified. In addition, please understand the following points:

  • The templates included with this project are subject to the License.
  • Generated code is intentionally not subject to the parent project license

When code is generated from this project, it shall be considered AS IS and owned by the user of the software. There are no warranties--expressed or implied--for generated code. You can do what you wish with it, and once generated, the code is your responsibility and subject to the licensing terms that you deem appropriate.

3.5 - IDE Integration

Here is a list of community-contributed IDE plug-ins that integrate with OpenAPI Generator:

4 - Companies/Projects using OpenAPI Generator

Here are some companies/projects (alphabetical order) using OpenAPI Generator in production. To add your company/project to the list, please visit README.md and click on the icon to edit the page.

5 - Presentations/Videos/Tutorials/Books

6 - About Us

What's the design philosophy or principle behind OpenAPI Generator?

We focus on developer experience. The generators should produce code, config, documentation, and more that are easily understandable and consumable by users. We focused on simple use cases to start with (bottom-up approach). Since then the project and the community have grown a lot: 600k weekly downloads via NPM CLI wrapper, 30M downloads via openapi-generator-cli docker image just to highlight a few. We've gradually supported more features (e.g. oneOf, anyOf introduced in OpenAPI 3.0) in various generators and we will continue this approach to deliver something based on our understanding of user demand and what they want, and continue to add support of new features introduced in OpenAPI specification (such as v3.1 and future versions of the OpenAPI specification).

6.1 - OpenAPI Generator Core Team

OpenAPI Generator 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.

Core Team Members

:heart: = Link to support the contributor directly

Template Creator

NOTE: Embedded templates are only supported in Mustache format. Support for all other formats is experimental and subject to change at any time.

Here is a list of template creators:

  • API Clients:
    • Ada: @stcarrez
    • Apex: @asnelling
    • Bash: @bkryza
    • C: @PowerOfCreation @zhemant :heart:
    • C++ REST: @Danielku15
    • C++ Tiny: @AndersSpringborg @kaareHH @michelealbano @mkakbas
    • C++ UE4: @Kahncode
    • C# (.NET 2.0): @who
    • C# (.NET Standard 1.3 ): @Gronsak
    • C# (.NET 4.5 refactored): @jimschubert :heart:
    • C# (GenericHost): @devhl-labs
    • C# (HttpClient): @Blackclaws
    • Clojure: @xhh
    • Crystal: @wing328
    • Dart: @yissachar
    • Dart (refactor): @joernahrens
    • Dart 2: @swipesight
    • Dart (Jaguar): @jaumard
    • Dart (Dio): @josh-burton
    • Elixir: @niku
    • Elm: @eriktim
    • Eiffel: @jvelilla
    • Erlang: @tsloughter
    • Erlang (PropEr): @jfacorro @robertoaloi
    • Groovy: @victorgit
    • Go: @wing328 :heart:
    • Go (rewritten in 2.3.0): @antihax
    • Haskell (http-client): @jonschoning
    • Java (Feign): @davidkiss
    • Java (Retrofit): @0legg
    • Java (Retrofit2): @emilianobonassi
    • Java (Jersey2): @xhh
    • Java (okhttp-gson): @xhh
    • Java (RestTemplate): @nbruno
    • Java (Spring 5 WebClient): @daonomic
    • Java (Spring 6 RestClient): @nicklas2751
    • Java (RESTEasy): @gayathrigs
    • Java (Vertx): @lopesmcc
    • Java (Google APIs Client Library): @charlescapps
    • Java (Rest-assured): @viclovsky
    • Java (Java 11 Native HTTP client): @bbdouglas
    • Java (Apache HttpClient 5.x): @harrywhite4 @andrevegas
    • Java (Helidon): @spericas @tjquinno @tvallin
    • Javascript/NodeJS: @jfiala
    • JavaScript (Apollo DataSource): @erithmetic
    • JavaScript (Closure-annotated Angular) @achew22
    • JavaScript (Flow types) @jaypea
    • Jetbrains HTTP Client : @jlengrand
    • JMeter: @davidkiss
    • Julia: @tanmaykm
    • Kotlin: @jimschubert :heart:
    • Kotlin (MultiPlatform): @andrewemery
    • Kotlin (Volley): @alisters
    • Kotlin (jvm-spring-webclient): @stefankoppier
    • Kotlin (jvm-spring-restclient): @stefankoppier
    • Lua: @daurnimator
    • N4JS: @mmews-n4
    • Nim: @hokamoto
    • OCaml: @cgensoul
    • Perl: @wing328 :heart:
    • PHP (Guzzle): @baartosz
    • PHP (with Data Transfer): @Articus
    • PowerShell: @beatcracker
    • PowerShell (refactored in 5.0.0): @wing328
    • Python: @spacether [:heart:][spacether sponsorship]
    • Python-Experimental: @spacether [:heart:][spacether sponsorship]
    • Python (refactored in 7.0.0): @wing328
    • R: @ramnov
    • Ruby (Faraday): @meganemura @dkliban
    • Ruby (HTTPX): @honeyryderchuck
    • Rust: @farcaller
    • Rust (rust-server): @metaswitch
    • Scala (scalaz & http4s): @tbrown1979
    • Scala (Akka): @cchafer
    • Scala (sttp): @chameleon82
    • Scala (sttp4): @flsh86
    • Scala (Pekko): @mickaelmagniez
    • Swift: @tkqubo
    • Swift 3: @hexelon
    • Swift 4: @ehyche
    • Swift 5: @4brunu
    • Swift Combine: @dydus0x14
    • TypeScript (Angular1): @mhardorf
    • TypeScript (Angular2): @roni-frantchi
    • TypeScript (Angular6): @akehir
    • TypeScript (Angular7): @topce
    • TypeScript (Axios): @nicokoenig
    • TypeScript (Fetch): @leonyu
    • TypeScript (Inversify): @gualtierim
    • TypeScript (jQuery): @bherila
    • TypeScript (Nestjs): @vfrank66
    • TypeScript (Node): @mhardorf
    • TypeScript (Rxjs): @denyo
    • TypeScript (redux-query): @petejohansonxo
    • Xojo: @Topheee
    • Zapier: @valmoz, @emajo
  • Server Stubs
    • Ada: @stcarrez
    • C# ASP.NET 5: @jimschubert :heart:
    • C# ASP.NET Core 3.0: @A-Joshi
    • C# APS.NET Core 3.1: @phatcher
    • C# Azure functions: @Abrhm7786
    • C# NancyFX: @mstefaniuk
    • C++ (Qt5 QHttpEngine): @etherealjoy
    • C++ Pistache: @sebymiano
    • C++ Restbed: @stkrwork
    • Erlang Server: @galaxie
    • F# (Giraffe) Server: @nmfisher
    • Go Server: @guohuang
    • Go Server (refactored in 7.0.0): @lwj5
    • Go (Echo) Server: @ph4r5h4d
    • Go (Gin) Server: @kemokemo
    • GraphQL Express Server: @renepardon
    • Haskell Servant: @algas
    • Haskell Yesod: @yotsuya
    • Java Camel: @carnevalegiacomo
    • Java MSF4J: @sanjeewa-malalgoda
    • Java Spring Boot: @diyfr
    • Java Undertow: @stevehu
    • Java Play Framework: @JFCote
    • Java PKMST: @anshu2185 @sanshuman @rkumar-pk @ninodpillai
    • Java Vert.x: @lwlee2608
    • Java Micronaut: @andriy-dmytruk
    • Java Helidon: @spericas @tjquinno @tvallin
    • Java WireMock: @acouvreur
    • JAX-RS RestEasy: @chameleon82
    • JAX-RS CXF: @hiveship
    • JAX-RS CXF (CDI): @nickcmaynard
    • JAX-RS RestEasy (JBoss EAP): @jfiala
    • Julia: @tanmaykm
    • Kotlin: @jimschubert :heart:
    • Kotlin (Spring Boot): @dr4ke616
    • Kotlin (Vertx): @Wooyme
    • Kotlin (JAX-RS): @anttileppa
    • Kotlin WireMock: @stefankoppier
    • NodeJS Express: @YishTish
    • PHP Flight: @daniel-sc
    • PHP Laravel: @renepardon
    • PHP Lumen: @abcsun
    • PHP Mezzio (with Path Handler): @Articus
    • PHP Slim: @jfastnacht
    • PHP Slim4: @ybelenko
    • PHP Symfony: @ksm2
    • PHP Symfony6: @BenjaminHae
    • Python FastAPI: @krjakbrjak
    • Python AIOHTTP:
    • Ruby on Rails 5: @zlx
    • Rust (rust-server): @metaswitch
    • Scala Akka: @Bouillie
    • Scala Cask: @aaronp
    • Scala Finch: @jimschubert :heart:
    • Scala Lagom: @gmkumar2005
    • Scala Play: @adigerber
  • Documentation
    • AsciiDoc: @man-at-home
    • HTML Doc 2: @jhitchcock
    • Confluence Wiki: @jhitchcock
    • PlantUML: @pburls
  • Configuration
    • Apache2: @stkrwork
    • k6: @mostafa
  • Schema
    • Avro: @sgadouar
    • GraphQL: @wing328 :heart:
    • Ktorm: @Luiz-Monad
    • MySQL: @ybelenko
    • Postman Collection: @gcatanese
    • Protocol Buffer: @wing328
    • WSDL: @adessoDpd

:heart: = Link to support the contributor directly

How to join the core team

Here are the requirements to become a core team member:

To join the core team, please reach out to team@openapitools.org 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.

6.2 - OpenAPI Generator Technical Committee

Members of the OpenAPI Generator technical committee shoulder the following responsibilities:

  • Provides guidance and direction to other users
  • Reviews pull requests and issues
  • Improves the generator by making enhancements, fixing bugs or updating documentations
  • Sets the technical direction of the generator

Who is eligible? Those who want to join must have at least 3 PRs merged into a generator. (Exceptions can be granted to template creators or contributors who have made a lot of code changes with less than 3 merged PRs)

If you want to join the committee, please kindly apply by sending an email to team@openapitools.org with your Github ID.

Members of Technical Committee

Languages/GeneratorsMember (join date)
ActionScript
Ada@stcarrez (2018/02) @michelealbano (2018/02)
Android@jaz-ah (2017/09)
Apex
Bash@frol (2017/07) @bkryza (2017/08) @kenjones-cisco (2017/09)
C@zhemant (2018/11) @ityuhui (2019/12) @michelealbano (2020/03)
C++@ravinikam (2017/07) @stkrwork (2017/07) @etherealjoy (2018/02) @martindelille (2018/03) @muttleyxd (2019/08)
C#@mandrean (2017/08) @shibayan (2020/02) @Blackclaws (2021/03) @lucamazzanti (2021/05) @iBicha (2023/07)
Clojure
Crystal@cyangle (2021/01)
Dart@jaumard (2018/09) @josh-burton (2019/12) @amondnet (2019/12) @sbu-WBT (2020/12) @kuhnroyal (2020/12) @agilob (2020/12) @ahmednfwela (2021/08)
Eiffel@jvelilla (2017/09)
Elixir@mrmstn (2018/12)
Elm@eriktim (2018/09)
Erlang@tsloughter (2017/11) @jfacorro (2018/10) @robertoaloi (2018/10)
F#@nmfisher (2019/05)
Go@antihax (2017/11) @grokify (2018/07) @kemokemo (2018/09) @jirikuncar (2021/01) @ph4r5h4d (2021/04) @lwj5 (2023/04)
GraphQL@renepardon (2018/12)
Groovy
Haskell
Java@bbdouglas (2017/07) @sreeshas (2017/08) @jfiala (2017/08) @lukoyanov (2017/09) @cbornet (2017/09) @jeff9finger (2018/01) @karismann (2019/03) @Zomzog (2019/04) @lwlee2608 (2019/10) @martin-mfg (2023/08)
Java Spring@cachescrubber (2022/02) @welshm (2022/02) @MelleD (2022/02) @atextor (2022/02) @manedev79 (2022/02) @javisst (2022/02) @borsch (2022/02) @banlevente (2022/02) @Zomzog (2022/09) @martin-mfg (2023/08)
JMeter@kannkyo (2021/01)
Jetbrains HTTP Client@jlengrand (2023/01)
Julia@tanmaykm (2023/01)
Kotlin@dr4ke616 (2018/08) @karismann (2019/03) @Zomzog (2019/04) @andrewemery (2019/10) @4brunu (2019/11) @yutaka0m (2020/03) @stefankoppier (2022/06)
Lua@daurnimator (2017/08)
N4JS@mmews-n4 (2023/03)
Nim
NodeJS/Javascript@CodeNinjai (2017/07) @frol (2017/07) @cliffano (2017/07)
ObjC
OCaml@cgensoul (2019/08)
Perl@wing328 (2017/07) :heart: @yue9944882 (2019/06)
PHP@jebentier (2017/07), @dkarlovi (2017/07), @mandrean (2017/08), @jfastnacht (2017/09), @ybelenko (2018/07), @renepardon (2018/12)
PowerShell@wing328 (2020/05)
Python@cbornet (2017/09) @tomplus (2018/10) @krjakbrjak (2023/02) @fa0311 (2023/10) @multani (2023/10)
R@Ramanth (2019/07) @saigiridhar21 (2019/07)
Ruby@cliffano (2017/07) @zlx (2017/09) @autopp (2019/02)
Rust@frol (2017/07) @farcaller (2017/08) @richardwhiuk (2019/07) @paladinzh (2020/05) @jacob-pro (2022/10)
Scala@clasnake (2017/07), @shijinkui (2018/01), @ramzimaalej (2018/03), @chameleon82 (2020/03), @Bouillie (2020/04) @fish86 (2023/06)
Swift@jgavris (2017/07) @ehyche (2017/08) @Edubits (2017/09) @jaz-ah (2017/09) @4brunu (2019/11) @dydus0x14 (2023/06)
TypeScript@TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @topce (2018/10) @akehir (2019/07) @petejohansonxo (2019/11) @amakhrov (2020/02) @davidgamero (2022/03) @mkusaka (2022/04)
Xojo@Topheee (2023/04)

Past Members of Technical Committee:

Languages/GeneratorsMember (join date)
Python@taxpon (2017/07) @frol (2017/07) @mbohlool (2017/07) @cbornet (2017/09) @kenjones-cisco (2017/11) @tomplus (2018/10) @arun-nalla (2019/11)

:heart: = Link to support the contributor directly

6.3 - History of OpenAPI Generator

OpenAPI Generator is a fork of Swagger Codegen. In view of the issues with the Swagger Codegen 3.0.0 (beta) release and the disagreement on the project's direction, more than 40 top contributors and template creators of Swagger Codegen decided to fork Swagger Codegen and maintain a community-driven version called "OpenAPI Generator". Please refer to the Q&A for more information.

Founding Members (alphabetical order):

:heart: = Link to support the contributor directly

7 - License

Copyright 2018 OpenAPI-Generator Contributors (https://openapi-generator.tech) Copyright 2018 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 apache.org/licenses/LICENSE-2.0

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.

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