Regular Expression Tester & Debugger

Test JavaScript regular expressions with real-time match highlighting, capture groups, and flag controls.

100% Client-Side — your text never leaves this browser. Works offline. How it works

0 lines • 0 bytes
Results update as you type
0Words
0Characters
0Chars (No Spaces)
0Sentences
0Paragraphs
0.0 minReading Time
0.0 minSpeaking Time
Your text
Counts update as you type
1

Social media limits

Top keywords

Type or paste text to see keyword frequency
About this tool

About the Regex Tester

Test and debug JavaScript regular expressions in real time. Highlight match occurrences, capture groups, and validate regex syntax with zero server transmission.

Real-Time Match Highlights

Instantly highlights matching text blocks with alternating visual contrast colors.

Capture Group Breakdown

Inspect captured groups ($1, $2, named groups) for each match occurrence in an organized table.

RegExp Flag Toggles

Quickly toggle global (g), case-insensitive (i), multiline (m), and dotAll (s) flags.

Syntax Error Diagnostics

Reports unescaped parentheses, invalid ranges, and quantifier syntax errors as you type.

FAQ

Common questions

Which regular expression dialect is supported?

Standard ECMAScript / JavaScript RegExp syntax with full modern support (named groups, unicode, lookaheads, lookbehinds).

What do regex flags like g, i, and m do?

g finds all matches (global), i ignores letter casing, and m treats ^ and $ as start and end of each line.

Can I copy the matched strings directly?

Yes, copy all matches or export match occurrences as a clean JSON array.

Does testing regex send my test data to a server?

Never. All RegExp execution runs 100% inside your browser environment.

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