- Facebook’s NTP Libraries on Github
GitHub Libraries: NTP protocol implementationand Chrony and ntpd control protocol implementations. - Cloudflare’s cfnts Libraries on GitHub
GitHub Libraries: cfnts implementation of the NTS protocol written in Rust. - Public Time Servers
List of public time servers on Github. - Build a Raspberry Pi Time Server
Instructions on how to build a secure stratum 1 timeserver using a Raspberry Pi and a simple GPS expansion board.