testssl.sh

testssl.sh is a command-line tool that checks TLS and SSL support on any port. It probes the ciphers, protocols, and known cryptographic flaws a service accepts, so you can see exactly how strong its encryption is before trusting it.

Results come as clear human-readable output plus CSV, two JSON formats, and HTML for reports and pipelines. It needs no extra setup and works against any SSL/TLS or STARTTLS service, not just web servers on port 443, with command-line flags to scope and shape each test.

Written in bash, it runs on Linux, macOS, the BSDs, and Windows through WSL2, MSYS2, or Cygwin, and ships a Docker image for container-based scans. It is open under GPLv2.