How to Use the Interactive Regular Expression Tester & Cheat Sheet
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1
Enter your regular expression pattern in the regex box (e.g. `[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}`).
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2
Toggle regex flags: Global (g), Case-Insensitive (i), Multiline (m), DotAll (s).
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3
Paste your test text in the test box and view colored match highlights and capture group breakdowns instantly.
Practical Example & Use Case
Common Real-World Scenario
Debugging a complex email or phone number validation regex against 20 edge-case test strings in real-time.
Technical Notes & Limitations
Browser Engine Architecture
Executes against the native browser V8 JavaScript RegExp engine with timeout guards to prevent catastrophic backtracking.
Frequently Asked Questions
Does this support named capture groups?
Yes! Modern JavaScript named groups `(?