We're working on a demo for Hacker News REST API mocking in the Android client integration tests, and as a part of it we've assembled an OpenAPI specification for its endpoints provided by Firebase. It's based on the existing documentation and examples. Feedback will be appreciated!

WTH is OpenAPI we use? OpenAPI is an open standard, originally inherited from Swagger. It can be used to serve the docs on the website, IDE integrations, to generate client code and to create various API mocks for the integration tests.

If you want to generate a Java client for testing, you can use Fern to generate one: https://github.com/fern-api/fern-java

disclaimer: I'm a maintainer of Fern.

Yeah, there are many projects for client generation from OpenAPI, and the number keeps growing. Make sure to add your tool to https://tools.openapis.org/ !