acme.sh

Issue, renew, and install TLS certificates through an ACME service with acme.sh, including no-cost certificates issued by Let’s Encrypt. Its single Shell script automates these certificate operations, so it can handle both initial issuance and subsequent renewals.

The client implements the ACME protocol across versions 1 and 2, with ACME v2 support for wildcard certificates. It can complete certificate tasks automatically without root or sudoer access, which suits administrators managing services under restricted permissions. The script runs with bash, dash, or sh and does not depend on Python or the official Let’s Encrypt client.

Following a KISS design, acme.sh avoids installing Cygwin, MSYS, MSYS2, curl, or OpenSSL alongside it. Docker-friendly operation and IPv6 support extend its usefulness across containerized deployments and networks using the newer IP protocol. Published by Neilpang, acme.sh is listed for Windows and distributed as freeware, while its shell-based design is aimed at users who want a compact certificate client rather than a larger client installation.