⌘ K
ipv6 · compressed · batch · local

Validate any IPv6 address with a regex

Accepts the full eight-group form as well as common compressed :: shorthand. Validate one address or a whole list.

IPv6 Validator
Mode
single
one value
Valid
1
ok
Invalid
0
fail
Pattern
ipv6
IPv6
Mode
input · single value
samples:
output · result
okValid
Pattern · IPv6 /^(?:[A-Fa-f0-9]{1,4}:){7}[A-Fa-f0-9]{1,4}$|^::(?:[A-Fa-f0-9]{1,4}:){0,6}[A-Fa-f0-9]{1,4}$|^[A-Fa-f0-9:]+::[A-Fa-f0-9:]*$/
Quick Start

How to validate an IPv6 address

Paste an address or a batch and read pass/fail per line — compressed and uncompressed forms accepted.

  1. 01

    Type an address

    Drop in any IPv6 candidate, compressed or full.

    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 · literalvalue · regex
    fe80::1
    loaded · ECMAScriptPCRE · ready
  2. 02

    Switch to batch

    Validate dozens of addresses one per line.

    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 · optionsmode · flags
    2001:db8::1
    flags applied · liveECMA · live
  3. 03

    Read the verdict

    Each line gets pass/fail. Copy or download the report.

    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 ::1
    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 toolsIpv4 ValidatorMac Address ValidatorUrl Pattern ValidatorUuid ValidatorRegex TesterRegex Library
Use Cases

When to validate IPv6

Config inputs, log fields, dual-stack rollouts.

Dual-stack rollout

Catch typos in config files. 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

Network audit

Filter IPv6 addresses from log fields. 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

Form input

Reject bad IPs at signup or admin UI. 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 data

Validate test addresses before commit. 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

Bulk lists

Trim invalid rows from a CSV. 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

Inventory tools

Sanity-check device records. 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

Not by default — the standard IPv6 pattern is hex-only. Build a stricter pattern with the Regex Builder if needed.
Not in the default pattern. fe80::1%eth0 won't match — strip the zone first or extend the pattern.
It accepts most common forms but isn't a complete RFC parser. Pair with a real library when needed.
Yes — open the Regex Tester with this pattern preloaded to tweak freely.
No. The tool runs entirely in your browser — your pattern and sample text never leave the page.
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