From Get docs
This guide is aimed at giving a quick introduction for those wishing to develop their own extensions for Sphinx. Sphinx possesses significant extensibility capabilities including the ability to hook into almost every point of the build process. If you simply wish to use Sphinx with existing extensions, refer to Using Sphinx. For a more detailed discussion of the extension interface see Developing extensions for Sphinx.
- Developing extensions overview
- Extension tutorials
- Configuring builders