IPv6 regex pattern

Copy and test a JavaScript regex for IPv6 addresses, with examples, limitations, and a one-click link to the regex tester.

Use anchors to check whether the complete value matches.

Regex: ^(?:(?:[0-9a-f]{1,4}:){7}[0-9a-f]{1,4}|(?:[0-9a-f]{1,4}:){1,6}:[0-9a-f]{1,4}|(?:[0-9a-f]{1,4}:){1,7}:|:(?::[0-9a-f]{1,4}){1,7})$

Flags: i

Find matching fragments inside a larger block of text.

Regex: (?:(?:[0-9a-f]{1,4}:){7}[0-9a-f]{1,4}|(?:[0-9a-f]{1,4}:){1,6}:[0-9a-f]{1,4}|(?:[0-9a-f]{1,4}:){1,7}:|:(?::[0-9a-f]{1,4}){1,7})

Flags: gi

Limitations

This practical pattern covers common IPv6 forms but not every rare representation such as IPv4-mapped variants.