Which regex flavor is this?

JavaScript (the same engine as your browser). Most syntax transfers to Python, Java and PCRE, but lookbehind and some advanced features differ between flavors - always re-test in your target language.

Why is my pattern marked invalid?

The error message shows the browser's exact complaint - usually an unclosed bracket, a stray backslash, or a bad quantifier. Fix it in the pattern box and highlighting resumes instantly.

What's the difference between the g and m flags?

g (global) finds all matches instead of stopping at the first. m (multiline) makes ^ and $ match at line boundaries, not just the string's start/end. They're independent - you often want both.

How do capture groups work here?

Parentheses create numbered groups. Each match row expands to show group 1, 2, 3… with their captured text - use (?:…) for non-capturing groups when you don't need the value.

Is catastrophic backtracking a risk?

In this tester, a runaway pattern just freezes your tab briefly - close it if needed. In production code, avoid nested quantifiers like (a+)+ and prefer atomic groups or possessive quantifiers where your flavor supports them.

Developer Tools

مختبر التعابير النمطية

التعبير النمطي لا يطابق ولا ترى السبب؟ الصق نمطك وسلسلة الاختبار - تضيء المطابقات حيًا أثناء التصحيح.

Pattern (without the / slashes /)

Flags

Test string

Common patterns

Regex cheatsheet

Character classes

.: Any character except newline
\d / \D: Digit / non-digit
\w / \W: Word char (A-Za-z0-9_) / non-word
\s / \S: Whitespace / non-whitespace
[abc]: Any of a, b, c
[^abc]: Anything except a, b, c
[a-z]: Range a through z

Quantifiers

*: 0 or more (greedy)
+: 1 or more (greedy)
?: 0 or 1
{n}: Exactly n
{n,}: n or more
{n,m}: Between n and m
*? +? ??: Lazy versions: match as little as possible

Anchors

^: Start of string (or line with m flag)
$: End of string (or line with m flag)
\b: Word boundary
\B: Not a word boundary

Groups

(abc): Capture group: numbered 1, 2, 3…
(?:abc): Non-capturing group
(?<name>abc): Named capture group
a|b: Alternation: a or b
\1: Backreference to group 1
(?=abc): Positive lookahead
(?!abc): Negative lookahead

Private by design: This tool runs entirely in your browser. Nothing you type or upload is sent to a server.

طريقة الاستخدام مختبر التعابير النمطية

أدخل نمطك. اكتب التعبير النمطي دون شرطات مائلة، ثم بدّل الأعلام (g وi وm وs وu) حسب الحاجة.
أضف نص الاختبار. الصق السلسلة التي تطابقها - سجلات أو مدخلات نماذج أو أيًا كانت.
افحص المطابقات. تُبرَز المطابقات في النص؛ وتسرد اللوحة أدناه كل مطابقة مع مجموعات التقاطها.
جرّب إعدادًا مسبقًا. عالق؟ حمّل نمطًا شائعًا (بريد أو رابط أو تاريخ…) وكيّفه.