Simple, scalable UUID generation.


Copyright 2009-2010 Twitter, Inc. See included LICENSE file.


  • pure-Ruby

  • no MAC address scraping

  • no file-based locking

This library implements UUID format version 1, as specified in RFC 4122, with jitter in place of the mac address and sequence counter.


Install the gem:

sudo gem install simple_uuid


# Creating and getting a timestamp from the UUID
uuid = => <UUID#2278170300  .... >
uuid.to_time => Thu Aug 18 19:15:16 -0400 2011

# Given raw bytes from a source such as cassandra (using bytes from an existing UUID as an example)
bytes =
SimpleUUID::UUID.to_time(bytes) => Thu Aug 18 19:15:16 -0400 2011

Reporting problems

The support forum is here.

Patches and contributions are very welcome.