Implementing the OAuth client using a library

Integrating an existing OAuth library into your application

Many open source libraries offer high-quality implementations of OAuth clients. They are available in a variety of programming languages, offering support for various web frameworks and database backends.


Where to start

A list of open-source OAuth client libraries is available at

We strongly recommend using one of these libraries instead of trying to implement OAuth from scratch

Implementing the client using a library

Libraries providing OAuth implementation often allow for some degree of customisation, allowing to plug in custom implementations for front-end and back-end interfaces they provide.

Most often, when using a library, a developer can:

  • configure the client for use with specific authorization server: provide the authorization and token endpoints, configure supported client authentication methods and protocol extensions;
  • provide the UI for initiating the flow (”Connect to Pleo” button), and connect it to functions and methods of the library that generate all necessary authorization request parameters;
  • integrate the library with the web framework of choice to allow it to perform HTTP redirects;
  • provide implementation for persistence backend, allowing the client library to store and retrieve parameters, such as code_verifier and state, as well as access and refresh tokens;
  • provide custom UI for handling success and error responses from the authorization server;
  • listen to events emitted during flow, and extend various stages.

Exact details and capabilities vary between implementations. Consult the documentation of the library of your choice.

What’s Next

Configure your implementation to work with Pleo OAuth servers