h is the web app that serves most of the https://hypothes.is/ website, including the web annotations API at https://hypothes.is/api/. The Hypothesis client is a browser-based annotator that is a client for h's API.
See the Contributor's guide for instructions on setting up a development environment and contributing to h.
If you'd like to contribute to the project, you should also subscribe to the development mailing list and read our Contributor's guide. Then consider getting started on one of the issues that are ready for work.
Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.