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Online Regex Tester: Test Regular Expressions with Live Matching

Tooly · 2026-08-02 · 5 min read

Regular expressions are powerful and finicky: one misplaced character and your pattern matches nothing — or worse, everything. An online regex tester shows you matches live as you type, so you can build and debug patterns in seconds instead of guessing.

What a regex tester does

• Live matching — see every match highlighted as you type
• Validation — instant feedback when your pattern is invalid
• Flags — global (g), case-insensitive (i), multiline (m)
• Match details — positions and counts for every hit

Test regex online with Tooly

The Tooly Regex Tester covers it:

• Paste your pattern and test text — matches update live
• Toggle g, i, and m flags with checkboxes
• See match count and each match's position
• 100% client-side — your patterns never leave your browser

Handy patterns to start with

• \b[\w.-]+@[\w-]+\.[\w.]+\b — emails
• \+?[0-9\s-]{10,15} — phone numbers
• https?:\/\/[\w.-]+ — URLs
• \d{4}-\d{2}-\d{2} — dates (YYYY-MM-DD)

Common pitfalls

• Forgetting to escape . (use \. for a literal dot)
• Missing the g flag — you only get the first match
• Anchors ^/$ not matching where you expect in multiline text
• Greedy quantifiers matching too much — try *? for lazy

Frequently Asked Questions

Is this regex tester really free? Yes — unlimited testing, no account, no watermark.

Is my pattern uploaded? No — everything runs in your browser, so your regex and test data stay on your device.

Does it support JavaScript regex syntax? Yes — standard JS regex with g/i/m flags, matching what your code will run.

What else pairs with it? The JSON Formatter and URL Parser are favorite companions for API work.

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