Regex Tester

Test regular expressions online for free. Real-time regex matching and highlighting.

✓ Free✓ No sign-up✓ Works in browser

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Regular Expression

gGlobaliCase insensitivemMultiline

Common Patterns

Test String

Highlighted Matches

2 matches

Match List

hello@freetoolkit.io

support@example.com

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How to Use This Tool

Enter Your Regex Pattern

Type your regular expression in the pattern field. The forward slashes and flag fields follow standard regex syntax.

Set Flags

Check the flags you need: g for global (find all matches), i for case-insensitive, m for multiline mode.

Test Against Your String

Enter your test string in the lower field. Matches highlight in yellow instantly as you type. The match list shows all found matches.

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Frequently Asked Questions

What is a regular expression?

A regular expression (regex) is a sequence of characters that defines a search pattern. It is used in programming for string searching, validation, and text manipulation. Most programming languages support regex natively.

What do the flags g, i, and m mean?

The 'g' flag finds all matches (global). The 'i' flag makes matching case-insensitive. The 'm' flag makes ^ and $ match line starts and ends instead of string start and end.

Why does my regex work in testing but not in my code?

Different programming languages have slightly different regex implementations. JavaScript, Python, and Java have minor syntax differences. Test your regex in the same language you will be using.

How do I match a literal dot or parenthesis?

Special characters like . * + ? ( ) [ ] { } ^ $ | \ must be escaped with a backslash to be treated as literals. For example, \. matches a literal dot instead of any character.

About Regex Tester

Our Regex Tester is a free, fast, and privacy-friendly tool that works entirely in your browser. No files are ever uploaded to our servers — all processing happens locally.

Unlike competitors that impose daily limits or require account creation, FreeToolKit gives you unlimited access with zero sign-up. Whether you are a developer, student, designer, or business professional, this tool is built to save you time.