UUID regex

Matches UUID/GUID format.

/[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/gi

What it matches

The canonical 8-4-4-4-12 hexadecimal form, hyphen separated, with the i flag so both spellings match. That is the textual representation defined by RFC 4122 and the one produced by crypto.randomUUID() and by every database UUID column.

Railroad diagram

Read left to right. Every path through the diagram is a string the pattern accepts.

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Breakdown

gFind all matches instead of stopping after the first

iLetters match both upper and lower case

[0-9a-f]{8}Match one of: Literal "0"–Literal "9", Literal "a"–Literal "f", exactly 8 times

-Literal "-"

[0-9a-f]{4}Match one of: Literal "0"–Literal "9", Literal "a"–Literal "f", exactly 4 times

-Literal "-"

[0-9a-f]{4}Match one of: Literal "0"–Literal "9", Literal "a"–Literal "f", exactly 4 times

-Literal "-"

[0-9a-f]{4}Match one of: Literal "0"–Literal "9", Literal "a"–Literal "f", exactly 4 times

-Literal "-"

[0-9a-f]{12}Match one of: Literal "0"–Literal "9", Literal "a"–Literal "f", exactly 12 times

Test cases

Matches

550e8400-e29b-41d4-a716-446655440000
123e4567-e89b-12d3-a456-426614174000
F47AC10B-58CC-4372-A567-0E02B2C3D479

Does not match

550e8400e29b41d4a716446655440000
550e8400-e29b-41d4-a716-44665544
not-a-uuid

Caveats

It checks shape, not version. The version and variant bits live in the third and fourth groups and this pattern ignores both, so it accepts strings no generator would produce. It also rejects the braced {…} and urn:uuid: forms, and the 32-character unhyphenated spelling some APIs return.

More common patterns

Test this against your own input in the regex tester, browse the full pattern library, or check the syntax cheat sheet.