Boulder

Boulder is an ACME-based certificate authority, written in Go. Its README says it is the software that runs Let’s Encrypt, and that it verifies an applicant controls an identifier before it issues a certificate.

The README also says the software is intended only to support the Web PKI, that the Docker development environment is not suitable for production use, and that organizations evaluating it for production should look at another project.

Worth knowing

The README describes the software’s use for its operator and does not describe a use for site owners, so the record is a stub. The project has no homepage of its own; the service it runs is provided from letsencrypt.org.