About this project

acme.sh is an ACME protocol client implemented entirely as a Unix shell script, used to automate the issuance, renewal and installation of SSL/TLS certificates. It implements the ACME protocol and works with RFC8555-compliant certificate authorities, including ZeroSSL (the default), Let's Encrypt, SSL.com, Google Public CA and Actalis. It supports ECDSA certificates as well as SAN and wildcard certificates. The project emphasizes portability: it runs under Bash, dash and sh, has no Python dependency, does not require root or sudoer access for basic use, and is described as Docker-ready and IPv6-ready. Installation can be done online via curl or wget from get.acme.sh, or from a Git clone using the built-in --install command, which copies the script to ~/.acme.sh, creates an alias and sets up a daily cron job to check and renew certificates. Certificates are renewed automatically by default every 30 days, and cron notifications can report renewal or errors. Validation modes include webroot, standalone (port 80), standalone tls-alpn (port 443), Apache, Nginx, DNS, DNS alias, stateless and DNS persist modes. For DNS validation, the project documents support for many DNS provider APIs, allowing unattended issuance; a manual DNS mode is also available but cannot renew automatically. After issuance, certificates can be installed to Apache, Nginx or other services with --install-cert, specifying cert, key and fullchain paths plus a reload command so the server picks up renewed certificates. The README lists tested platforms including macOS, Windows (cygwin), FreeBSD, OpenBSD, NetBSD, DragonFlyBSD, MidnightBSD, Solaris, OmniOS, OpenIndiana, several Linux distributions, Haiku, Tribblix, GhostBSD, GNU Hurd, openEuler, HardenedBSD and OPNsense, with CI badges for each. Release tags from 3.1.5 onward are signed with the maintainer's SSH key, and the repository includes an allowed_signers file for verification. The README also notes adoption by projects and organizations such as FreeBSD.org, Proxmox, pfsense, OPNsense, Discourse and others.