PHP (PCRE) Regex Tester

Test regular expressions written for PHP (PCRE) (PCRE2 (preg_*)) — with warnings for anything that works differently there, and PHP (PCRE) code to copy.

//g

gglobaliinsensitivemmultilinesdotAll

Test String

PHP (PCRE) regex syntax at a glance

Literal: '/pattern/flags' with delimiters — escape / inside, or use # or ~ as the delimiter
Named group: (?<name>…), (?P<name>…) or (?'name'…)
Replacement: $1, ${1}, \1 in preg_replace
Flags: i, m, s, x, u (UTF-8), D (dollar end only)
Find all: preg_match_all('/…/', $text, $matches)

What's different in PHP (PCRE)

→PCRE is also what nginx, Apache, grep -P and many tools use, so this page fits their patterns too.
→Add the u modifier for UTF-8 text, or multibyte characters are treated as separate bytes.
→Recursion (?R), conditionals, possessive quantifiers and atomic groups are all supported.
→Variable-length lookbehind needs PCRE2 10.43+ (PHP 8.4); older versions want fixed-length lookbehind.

Frequently asked

Why do I get "No ending delimiter '/' found"?

PHP regexes need delimiters: '/\d+/' not '\d+'. If the pattern contains /, escape it as \/ or pick another delimiter like #…#.

Does nginx use the same regex syntax?

Yes — nginx location and rewrite rules use PCRE, so named groups, lookarounds and the flags here behave the same. The case-insensitive form is written ~* in nginx.