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uuid · v1-v5 · version detect · batch

Validate any UUID with a regex

Check UUIDs (v1–v5) for valid format with version and variant nibble verification. Single or batch. Runs locally.

UUID Validator
Mode
single
one value
Valid
1
ok
Invalid
0
fail
Pattern
uuid
v1–v5
Mode
input · single value
samples:
output · result
okValid
version: v4
Pattern · v1–v5 /^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89ABab][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$/
Quick Start

How to validate a UUID

Type or paste UUIDs and confirm version (1-5) plus variant nibble.

  1. 01

    Pick mode

    Single for one UUID, batch for many lines.

    Patterns compile through the JavaScript RegExp constructor, so syntax errors surface immediately and engine quirks like Unicode property escapes (\p{L}) work when the u flag is on.

    patternECMAScriptliterallive
    input · literalmode · regex
    Single | Batch
    loaded · ECMAScriptPCRE · ready
  2. 02

    Type or paste

    8-4-4-4-12 hex with dashes. Case-insensitive.

    Each flag character mirrors the ECMAScript literal: g enables iteration, i folds case, m anchors per line, s lets . match newlines, u unlocks proper Unicode, y is sticky, and d emits indices.

    flagsoptionsg · i · mlive
    config · optionsvalue · flags
    550e8400-e29b-41d4-…
    flags applied · liveECMA · live
  3. 03

    Read the verdict

    Valid UUIDs surface their detected version (v1, v3, v4, etc.).

    Watch for catastrophic backtracking on nested quantifiers — a common ReDoS source. The tool caps match counts to keep the page responsive on pathological patterns.

    matchgroupshighlightReDoS-safe
    run · outputresult · matches
    ok 550e8400-… v4
    matches · livegroups · live
  4. 04

    Copy or export

    Grab the output as JSON, CSV, or plain text — ready for your editor or pipeline.

    Copy writes via navigator.clipboard.writeText; downloads use a Blob and object URL, so nothing transits the network and the output is byte-identical to what you see on screen.

    copyexportclipboardblob
    export · exportedready · saved
    Copied
    ready to shipsuccess
Pro tips

Regex patterns that don't melt down

Use named groups

(?<year>\d{4}) reads better than $1 and survives reordering. Supported in ECMAScript 2018+.

Anchor strictly

Use ^/$ with the m flag when matching whole lines. Without anchors, partial matches sneak through.

Avoid catastrophic backtracking

Nested quantifiers like (a+)+ can explode. Run patterns through ReDoS Detector first.

Escape every literal

Backslash any meta character you want literally: \.\$\^\*\+\?\(\)\[\]\{\}\|\\.

Test edge cases

Empty string, single character, unicode, the maximum length you expect — write fixtures for each.

Patterns aren&rsquo;t parsers

Don’t parse HTML, JSON, or balanced parens with regex. Use a proper parser when the grammar is recursive.

Related toolsMac Address ValidatorIpv4 ValidatorIpv6 ValidatorRegex TesterRegex LibraryRegex Cheatsheet
Use Cases

When to validate UUIDs

API requests, log audits, fixture validation.

API request bodies

Reject malformed IDs at the edge. Compiles through the JavaScript RegExp constructor — engine quirks (Unicode property escapes, sticky matching, named groups) work when their flags are on. Error messages cite the exact position of any syntax issue.

ReDoS-safe

Log inspection

Confirm trace IDs look right. Pairs with the ReDoS detector to catch catastrophic backtracking before you deploy. A pattern that handles 1k-character input fine can become a denial-of-service vector on attacker-controlled 1M-character input.

ECMA-compliant

Database import

Find broken UUID columns in CSV. Output exports as JavaScript, Python re, Java util.regex, .NET System.Text.RegularExpressions, PCRE, and POSIX — language quirks are highlighted on conversion so you don't ship a JS-only pattern to a Go service.

spec-grade

Fixture audit

Sanity-check test data. Capture groups (named or numbered) round-trip cleanly into replacement strings, JSON output, or CSV extraction without re-typing. Backreferences ($1, ${name}) preserve semantics across languages.

cross-engine

Detect version

v4 (random) vs v5 (named) at a glance. Test against edge cases — empty input, single character, max length, multibyte boundaries — to catch off-by-one and zero-length match bugs before they reach production.

test-ready

Bulk lists

Paste hundreds and see which fail. All matching runs client-side so secret patterns never leave the browser. Useful when the pattern itself is sensitive (PII regexes, internal data formats, security filters).

production-ready
FAQ

Frequently asked questions

v1 through v5. v6, v7, v8 (draft) aren't in the pattern — open the Builder to add them.
No — it has version nibble 0, which the regex rejects. Allow it explicitly if needed.
No. Both uppercase and lowercase hex are accepted.
The first hex digit of the third group [89ABab] denotes the RFC 4122 variant. The pattern enforces it.
No. The tool runs entirely in your browser — your pattern and sample text never leave the page.
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