⌘ K
php · pcre · preg_match · local

Generate PHP code from a regex

Drop a pattern in, pick flags, and get a PCRE snippet — preg_match, preg_match_all, preg_replace, preg_split — wrapped in / delimiters with the right modifier letters.

Regex → PHP
//g
PHP (PCRE)
<?php
$pattern = '/\\\\b\\\\w+@\\\\w+\\\\.\\\\w+\\\\b/';
$input = 'Reach alice@example.com or bob@test.org.';

$isMatch = (bool) preg_match($pattern, $input);

preg_match($pattern, $input, $first);
preg_match_all($pattern, $input, $all);

$replaced = preg_replace($pattern, '[email]', $input);
$parts = preg_split($pattern, $input);

print_r([
    'isMatch' => $isMatch,
    'first' => $first[0] ?? null,
    'all' => $all[0] ?? [],
    'replaced' => $replaced,
    'parts' => $parts,
]);
Quick Start

How to use a regex in PHP

PHP's preg_* family uses PCRE, the closest cousin of Perl regex. Patterns are wrapped in delimiters (usually /.../) with optional modifier letters at the end.

  1. 01

    Type a pattern

    PCRE supports nearly everything JavaScript does plus a few extras (atomic groups, conditional patterns). Forward slashes are auto-escaped to play nice with / delimiters.

    Patterns are parsed with the JavaScript RegExp constructor, so syntax errors surface immediately and engine quirks like Unicode property escapes (\p{L}) require the u flag.

    patternECMAScriptliteralregex
    input · literalpattern · regex
    /\b\w+@\w+\b/
    loaded · ECMAScripttarget · ready
  2. 02

    Tune flags

    JS i/m/s/u/x map directly to PHP modifier letters. Append them after the closing delimiter — /pat/im.

    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.

    flagssampleg · i · mlive
    config · optionsflags · flags
    /pat/im
    flags applied · livelive · preview
  3. 03

    Read the snippet

    Includes preg_match (first), preg_match_all (every), preg_replace, preg_split, all printing into a single array.

    The generator rewrites the regex for the target language — handling string-literal escaping, raw-string prefixes, and engine-specific syntax tweaks.

    codegentargetsnippetcopy
    run · outputpreview · code
    preg_match($pat, …)
    snippet · livecode · ready
  4. 04

    Copy code

    One click copies the full snippet — paste into a .php file or run with php -r.

    Copy writes via navigator.clipboard.writeText, 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 To JavascriptRegex To PerlRegex TesterRegex ExplainerRegex BuilderRegex Replace
Use Cases

When to generate PHP regex code

Skip the boilerplate when wiring a pattern into a Laravel app, a WordPress plugin, or a legacy LAMP project.

Laravel validation

Wire preg_match into a custom validator rule. 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

WordPress filters

Use preg_replace inside a content filter hook. 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

URL rewriting

Apply patterns in Apache rewrite rules or PHP routing layers. 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

Log scraping

Run preg_match_all over a tail -f stream piped to a PHP CLI script. 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

Form normalisation

Sanitise user input before persisting to MySQL. 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

CMS migration

Bulk-transform legacy strings during a data migration. 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

PCRE patterns need delimiters. / is conventional, but you can use any non-alphanumeric character — handy when the pattern itself contains slashes. Pick a delimiter that doesn't appear in your pattern.
Either escape it (\/) or change the delimiter (use ~pattern~ instead of /pattern/). The tool auto-escapes / in your pattern when using the default / delimiter.
Enables PCRE's Unicode mode — required when matching multibyte characters like emoji or non-Latin scripts. Without it, character classes like \w match ASCII only.
PHP automatically caches the last ~4096 compiled patterns. You don't need to do anything — just use literal pattern strings and PCRE remembers.
No. The code is generated entirely in your browser.
Suggest a tool

Something missing?

Tell us what you need. We ship the top requests every two weeks.

Sent straight to the maintainers · no account needed
47 in queue·8 shipped this month
Request queued. Thanks!