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CODE UTILITIES

Regular Expression (Regex) Tester

Online regular expression (RegExp) tester and debugger. Test regex patterns in real time with match highlighting, capture groups, and flag toggles.

100% Client-Side Fast Private & Secure Free In-Browser Tool All Tools
/ / g
Flags:
2 Matches
About Regex Tester

What is Regular Expression (Regex) Tester & How Does It Work?

Test and debug complex regular expressions with real-time feedback. Enter your pattern, toggle regex flags, and immediately visualize all matching tokens highlighted directly within your test string.

100% Privacy & Security Guarantee

All operations execute locally inside your browser engine using JavaScript. Your confidential code, JSON datasets, tokens, and credentials are never stored, logged, or transmitted across external servers.

Key Features & Capabilities

Real-time pattern matching with live visual `<mark>` highlight badges
Interactive flag toggles: Global (`g`), Case-Insensitive (`i`), Multiline (`m`), dotAll (`s`), and Unicode (`u`)
Instant match counter badge and syntax error detection banner
Pre-loaded sample patterns for email verification, URLs, and phone numbers
100% Client-side execution with complete string privacy

How to Use Regular Expression (Regex) Tester (Step-by-Step Guide)

1
Enter Pattern

Type your regular expression pattern between the slashes `/.../`.

2
Configure Flags

Check or uncheck regex flags (Global, Case-Insensitive, Multiline) as needed.

3
Paste Test Text

Type or paste your test text into the test string area.

4
Inspect Matches

View all highlighted matches in the visual preview box and check total match count.

Frequently Asked Questions

This tester uses standard ECMAScript (JavaScript) regular expression specifications, which is compatible with modern browsers, Node.js, and most web frameworks.

Make sure the Global (`g`) flag is checked. Without the `g` flag, regular expressions only return the very first match found.
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JavaScript Regular Expressions Tutorial SQL Pattern Matching (LIKE & REGEXP)

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