Add the text, code or data.
01Developer toolFormatted output
Regex Tester
Test a pattern against text and count matches.
100% FreeRuns instantlyNo watermark
- 1Paste inputAdd the text, code or data.
- 2AdjustChoose formatting or generation options.
- 3RunProcess everything in the browser.
Private by designProcessed on your device where possible.
Works on any deviceDesktop, tablet and mobile browsers.
No installationOpen the page and start working.
Always free coreUse the free plan for everyday tasks.
How to use Regex Tester
Choose formatting or generation options.
02Process everything in the browser.
03Copy or download the clean result.
04Your files stay private
Your work is processed locally in your browser where possible and is never added to a Vootkit upload library.
Learn more about privacyRegular expressions are quicker to write than to verify. Testing a pattern against real text — including the awkward cases you would rather not think about — takes seconds and saves the bug that only appears on one row in ten thousand.
What Regex Tester does
Runs a regular expression against your text and shows what it matched.
Flags go in their own box. The default is g, which finds every match rather than stopping at the first — without it you will see one result and wrongly conclude the pattern is too narrow.
Flags and behaviour
| g | Global — find every match, not just the first (default) |
|---|---|
| i | Case-insensitive |
| m | Multiline — ^ and $ match at each line |
| s | Dot matches newlines too |
| u | Unicode mode |
| Matches shown | Up to the first 100 |
| Flavour | JavaScript regular expressions |
Detailed steps
- Enter your pattern — without the surrounding slashes.
- Set the flags. Leave
gunless you specifically want only the first match. - Paste text to test against, including the edge cases you expect to fail.
Worth knowing
Test the strings you expect NOT to match, not just the ones you do. Most regex bugs are over-matching rather than under-matching — a pattern that correctly finds every email address and also cheerfully accepts three lines of unrelated text.
Frequently Asked Questions
Only one match is showing.
The g flag is missing. Without it a regular expression stops at the first match. Put g in the flags box — it is there by default for exactly this reason.
My pattern works elsewhere but not here.
Regex flavours differ. This uses JavaScript’s engine, which lacks some constructs that PCRE, Python and .NET support — lookbehind support varies, and named group syntax is not identical. A pattern from a Perl or PHP example may need adjusting.
Do I include the slashes?
No. Enter the pattern alone and put the flags in their own box. Pasting /pattern/g whole makes the slashes part of the pattern, which then matches nothing.
Why are only 100 matches listed?
A display limit, so a pattern matching every character in a long document does not lock up the page. The pattern itself is unaffected — you are seeing a sample.
Is Regex Tester free?
Yes. The Vootkit free plan includes 5 tool runs a day. Upgrade to Vootkit Pro for unlimited daily use, an ad-free workspace and saved workflows.
Are my files uploaded?
No. Regex Tester runs entirely in your browser — your file is processed on your own device and never sent to a server. There is nothing for us to store or delete.
Do I need to install anything?
No. Regex Tester works in any modern browser on desktop, tablet or phone. Open the page and start.
How often can I use it? Is there a daily limit?
On the free plan you get 5 tool runs a day. When you reach the limit you'll see a prompt to upgrade, and it resets the next day. Vootkit Pro removes the cap entirely for unlimited daily use.
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This tool processes everything locally in your browser. You can disconnect from the internet after the page loads and it will still work.