Regex Tester
Test regular expressions online with live match highlighting, capture groups, and flag support (g, i, m, s). Built-in patterns for email, URL, phone, and more. No signup required.
Live Preview — 2 matches found
Match Details
3 Simple Steps
Write Your Pattern
Type a regex pattern or pick a ready-made one for email, URL, phone, or date.
Paste Test Text
Add the text you want to match against — matches highlight instantly as you type.
Check the Matches
See every match, its position, and any captured groups in the results list.
Why Use ConvertLinx?
Live Match Highlighting
See exactly what your pattern matches as you type — no need to run code or check a console.
Ready-Made Patterns
One click loads tested patterns for email, URL, phone number, date, IP address, and hex color.
Secure & Private
All matching runs in your browser using native JavaScript RegExp — your text never leaves your device.
Why Test Regex Before Using It in Code
Regular expressions are powerful but unforgiving — a single missing escape character or misplaced quantifier can silently match the wrong text, or nothing at all. Testing a pattern against real sample data before shipping it in form validation, search filters, or data parsing catches these mistakes early, before they reach production.
Whether you're validating an email field, extracting data from log files, or writing a find-and-replace pattern, a live regex tester saves the time of running your code repeatedly just to check if a pattern behaves the way you expect.
Understanding Regex Flags
The g (global) flag returns every match in the text instead of stopping at the first one. The i (ignore case) flag makes matching case-insensitive, so "Hello" and "hello" both match. The m (multiline) flag changes how ^ and $ behave, matching the start and end of each line rather than the whole string. The s (dot all) flag makes the . character match newlines too, which it normally does not.
Common Problems This Tool Solves
Who Should Use This?
Features
Best Uses for a Regex Tester
Frequently Asked Questions
Is the Regex Tester free?
Yes — completely free, unlimited testing, no signup required.
What regex flavor does this tool use?
It uses JavaScript's native RegExp engine — the same regex behavior you get in browsers, Node.js, and any JavaScript codebase.
What do the g, i, m, and s flags mean?
g (global) finds all matches instead of just the first. i (ignore case) makes matching case-insensitive. m (multiline) makes ^ and $ match the start/end of each line. s (dot all) makes . match newline characters too.
Why is my regex not matching anything?
Common reasons include forgetting to escape special characters (like . or ( ) ), using the wrong flags, or a typo in the pattern. Check the error message shown above the test area for invalid patterns.
Can I test regex with capture groups?
Yes — matches with capture groups (using parentheses) show each captured group separately in the match results list below the test area.
Is my test data uploaded anywhere?
No — all regex matching happens directly in your browser using JavaScript's built-in RegExp engine. Nothing is sent to any server.
Does this work for validating emails, URLs, or phone numbers?
Yes — use the quick pattern buttons to instantly load common patterns for email, URL, phone number, date, IP address, and hex color validation.
Why does my pattern throw a syntax error?
JavaScript regex requires certain characters to be escaped, like ( ) [ ] . * + ? and \. If you see an error, check for unmatched brackets or unescaped special characters.
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