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Text Utility Secure & Local

Regex Tester.

Test regular expressions (RegEx) against target strings. View matches, groups, substitutions, and adjust match flags client-side.

Regular Expression Valid

/ /
Presets:
Test String
Match Highlighting
Matches Info 0 matches
No matches found.

About Regex Tester

Regex Tester is a high-performance web utility built to test regular expressions (RegEx) against target strings. View matches, groups, substitutions, and adjust match flags client-side instantly and securely. Because it is designed with a local-first architecture, all processing occurs directly in your browser's memory using client-side JavaScript. This ensures that your files, code, or private text inputs are never uploaded to any external server or tracked by third-party analytics.

Whether you are formatting source code, cleaning text files, converting file structures, or running diagnostics, running these processes locally in your browser memory sandbox eliminates network latency and protects your data privacy.

Frequently Asked Questions (FAQs)

What is RegEx?

RegEx (Regular Expression) is a sequence of characters that forms a search pattern, used for string matching and text replacement.

How do I test my regex?

Input the expression, add search flags (g, i, m), paste your test string, and check highlighted match groups.

Are match groups supported?

Yes. The tester details individual capturing groups and offsets to help developers refine expressions.

Is my input string private?

Yes. The testing algorithms run client-side. No expression data is sent to external databases.

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