Email is the best way to reach me. There is no contact form here — a form needs a server to send it somewhere, and this site does not have one.
General enquiries
Anything at all: work, a question about one of the projects, or saying hello. If you are not sure which address to use, use this one.
Privacy
Questions about the website privacy policy or any of the applications' policies. Also the address to use if you appear in a photograph on the community page and would rather not — no explanation needed.
Reporting a bug
For anything wrong with the software itself, an issue on the project's own GitHub repository is better than an email: it is public, other people with the same problem can find it, and it stays attached to the code. Email is fine too.