Community
We can always use help answering questions at Let’s Encrypt Community Support. See this blog post about why community support contributions are so important.
Code
We can also use help with software development. All of our code and protocol specifications are on GitHub.
Client Software
Certbot is a Python-based utility that works alongside Apache to automatically obtain a certificate and convert a website to HTTPS.
Certbot software development can be discussed via IRC chat on OFTC.
Server-side CA Software
Boulder is the primary Let’s Encrypt CA implementation. It’s based on the ACME protocol, and written primarily in Go.
CA software development can be discussed on this mailing list. To subscribe without a Google account, send mail to ca-dev+subscribe@letsencrypt.org.
Protocol
The Let’s Encrypt CA talks to certificate management software running on web servers. The protocol for this is called ACME, for “Automated Certificate Management Environment.” You can view the draft ACME spec now. We plan to propose work on this protocol in the IETF soon, to make it a truly open standard.
ACME protocol development can be discussed on this IETF mailing list.