You can use the following mailing list hosted at Google Groups to ask technical and general questions related to Rspamd. Please mention that you need to join the mailing list before posting your questions.
Follow Rspamd on Twitter to receive the most recent news about the project, including release announces.
If you find a bug or would like to ask for a specific feature then you can use issue tracker hosted on GitHub. We also welcome pull requests if you would like to submit patches for any part of the project: documentation, site, WebUI, Rmilter and Rspamd itself.
If you would like to support Rspamd development, we are accepting donations via PayPal.
If you require the additional level of support related to large or custom Rspamd setup that could involve NDA signing, you might go with the commercial support option. Should you have any questions or queries about this option then please contact firstname.lastname@example.org for options and quotes.