🧪 Regex Tester
Test regular expressions live: matches, groups, flags and highlighted results, all locally in your browser.
🔐 The pattern is compiled and executed locally in your browser. Nothing is sent to 0Appz or any third party.
🎯 Highlighted result
0📋 Match details
📖 Quick reference
\ddigits\wword characters\swhitespace.any character+ * ?repetition (1+, 0+, optional)[abc]any character in the set( )capturing group^ $start / end of text
How to use this tool
Overview
Regex Tester - Free Online Regular Expression Tester lets you test regular expressions as you type. Enter a pattern, pick your flags (g, i, m, s, u), paste the test text and instantly see every match highlighted in place, with the match list showing positions and capture group values. Invalid patterns produce clear error messages instead of silent failures. A quick-reference cheat sheet for \d, \w, \s, quantifiers, sets, groups and anchors is included. The regex engine runs entirely in your browser — neither the pattern nor the text is uploaded, which matters for real-world data like logs, emails and CSVs.Frequently asked questions
What flavors of regex does this support? +
The Regex Tester - Free Online Regular Expression Tester uses the JavaScript RegExp engine, the same syntax used in browsers and Node.js — including the g, i, m, s and u flags.
What does each flag do? +
g finds all matches instead of just the first, i ignores case, m makes ^ and $ match line starts and ends, s makes the dot match newlines, and u enables full Unicode matching.
Why does my pattern show as invalid? +
The engine reports a clear error message under the pattern field, usually for unbalanced parentheses or brackets, invalid quantifiers, or unsupported escapes.
Is my text sent anywhere? +
No. The pattern and the test text stay entirely in your browser — nothing is sent to 0Appz or any third party.