It runs on Unix-like operating systems (including Linux and macOS) and is released under the GNU GPL v2.

[10] In contrast to NTPsec, which is a security-focused fork of ntpd, chrony was implemented from scratch.

[1] Some improvements in this regard (compared to reference ntpd) include that it never steps (abruptly adjusts) time outside of startup, can correct for asymmetric network jitters, and can use larger clock rate adjustments on Linux to deal with a broken clock.

It also supports synchronization by manual input, so as to perform time correction within an isolated network.

[4] It uses external programs to drive hardware time sources (e.g. gpsd for GNSS), unlike ntpd, which has many built-in drivers.