Integration
To integrate Goiabada with your app, you'll need to explore your platform for an OAuth2/OpenID Connect client library. Most of platforms provide such libraries for integration.
Javascript-only
The github repository of Goiabada has a browser-based javascript test client that you can use to test Goiabada. It uses the oauth4webapi library.
Go web app
We also have a sample integration using Go. Have a look here.
React SPA with Vite and NodeJS server
Take a look at this sample react application that uses authentication and role (group) based authorization, with token auto-refresh.