⌘ K
numbered to named · auto back-refs

Convert numbered groups to named groups

Find every capturing group in your regex, give each a name, and copy the rewritten pattern. Back-references update automatically. Runs locally.

Regex Group Renamer
Groups
3
capturing
Named
3
renamed
Length
44
chars
Status
ready
live
input · regex + names
Groups (3)
#1(
#2(
#3(
output · renamed pattern
Result
(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})
Quick Start

How to rename capture groups

Convert numbered groups into named groups by typing a name beside each #. Back-references are rewritten too.

  1. 01

    Paste pattern

    Drop your regex in. The renamer finds every (capturing) group and lists them.

    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 · literalregex · regex
    (\d{4})-(\d{2})-(\d{2})
    loaded · ECMAScriptPCRE · ready
  2. 02

    Name each group

    Type a name beside #1, #2, #3. Empty names keep the group anonymous.

    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 · optionsnames · flags
    #1 year #2 month #3 day
    flags applied · liveECMA · live
  3. 03

    Read converted output

    (?<year>...) replaces (...). Back-references like \1 become \k<year>.

    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 · outputconvert · matches
    (?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})
    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 toolsRegex TesterRegex ExplainerRegex Extract GroupsRegex CheatsheetRegex SimplifierRegex Character Classes
Use Cases

When to rename groups

Named groups make regex less brittle and more readable.

Modernise old regex

Replace fragile (...) groups with self-documenting names. 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

Refactor code reads

Use match.groups.year instead of match[1] in your code. 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

Document a regex

Names make the pattern self-describing in a PR. 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

Reduce bugs

Renumbering groups can break captures — named groups don't. 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

Migrate to Python

Names work in Python's re module too via (?P<name>). 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

Pair with explainer

Run the result through the explainer to verify intent. 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

No — only plain (...) and existing (?<name>...) groups are listed. (?:...), lookaheads, and lookbehinds are skipped.
Yes — \1, \2 etc. become \k<name> when the matching group has a name.
Leave the name input empty. That group stays as (...).
The output is checked with new RegExp() — invalid syntax shows an error inline.
No. The tool runs entirely in your browser — your pattern and sample text never leave the page.
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