Hearth's firmware, integrations, and supporting tooling are open source. Audit the code, build from source, fork the project, or replace parts piecemeal.
License
Hearth is released under the MIT License. In plain terms: use it, modify it, build on it, even ship it in a commercial product — just keep the copyright notice and the license text when you redistribute. No warranty, no strings.
Contributing
Issues and pull requests are welcome at the repo. For major changes, open a discussion first.
Building from source
Full build instructions live in the repo's README.md.