FusionAuth Client Builder 
Credits
Thanks to the following folks for your most excellent contributions!
Contributing
If you want to help us directly support and publish this library, there are a few ways you can help.
We start with a JSON DSL to define each API ( https://github.com/FusionAuth/fusionauth-client-builder/tree/master/src/main/api ).
We then build the code using a template, for example, here is the ruby template : https://github.com/FusionAuth/fusionauth-client-builder/blob/master/src/main/client/ruby.client.ftl
This ruby template then produces the ruby client.
https://github.com/FusionAuth/fusionauth-ruby-client
https://github.com/FusionAuth/fusionauth-ruby-client/blob/master/lib/fusionauth/fusionauth_client.rb
You can pick the current client library template for the language closest to the language you want to support. Let's say it is ruby. You will copy the ruby client template (https://github.com/FusionAuth/fusionauth-client-builder/blob/master/src/main/client/ruby.client.ftl) to .client.ftl and then start hacking on it.
With that template we can then build the client each time we release.
You can also build a library any other way; the chances of us supporting custom builds are low, but you can add your library to the contrib repo: https://github.com/FusionAuth/fusionauth-contrib/
Build a client library
Setup Savant
Linux or macOS
mkdir ~/savant
cd ~/savant
wget http://savant.inversoft.org/org/savantbuild/savant-core/1.0.0/savant-1.0.0.tar.gz
tar xvfz savant-1.0.0.tar.gz
ln -s ./savant-1.0.0 current
export PATH=$PATH:~/savant/current/bin/
You may optionally want to add ~/savant/current/bin to your PATH that is set in your profile so that this change persists. You'll also need to ensure that you have Java >= 8 installed and the environment variable JAVA_HOME is set.
Building
Listing each client library build targets
sb --listTargets
Building a single library
To build a single client library, you'll want to have the corresponding repo checked out in the same parent directory.
For example, your directory structure should look something like the following:
fusionauth
├── fusionauth-client-builder
├── fusionauth-android-client
├── fusionauth-csharp-client
├── fusionauth-java-client
├── fusionauth-javascript-client
├── fusionauth-node-client
├── fusionauth-openapi
├── fusionauth-php-client
├── fusionauth-python-client
├── fusionauth-ruby-client
├── fusionauth-swift-client
├── fusionauth-typescript-client
├── fusionauth-dart-client
└── go-client
The client builder will assume the project is in the same parent directory.
sb build-java
Building all clients
sb build-all
For more information on the Savant build tool, checkout savantbuild.org.