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Get the Roughtime

The "Hello, world!" of Roughtime is very simple: the client sends a request over UDP to the server and the server responds with a signed timestamp.

You just need the server's address and public key to run the protocol:

  • Server address: roughtime.cloudflare.com:2003 (resolves to an IP address in our anycast IP range ↗). You can use either IPv4 or IPv6.
  • Public key: 0GD7c3yP8xEc4Zl2zeuN2SlLvDVVocjsPSL8/Rl/7zg=

To get started, download and run Cloudflare's Go client ↗:

go install github.com/cloudflare/roughtime/cmd/getroughtime@latest
getroughtime -ping roughtime.cloudflare.com:2003 -pubkey 0GD7c3yP8xEc4Zl2zeuN2SlLvDVVocjsPSL8/Rl/7zg=

Beta notice

Cloudflare Roughtime is currently in beta. As such, our root public key may change in the future. We will keep this page up-to-date with the most current public key.

You can also obtain it programmatically using DNS. For example:

Terminal window
dig TXT roughtime.cloudflare.com | grep -oP 'TXT\s"\K.*?(?=")'

Next steps

Beyond just getting the Roughtime from Cloudflare, you may want to use it to keep your clock in sync.