Which regex engine is used?

It uses the native JavaScript RegExp engine built into your web browser.

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Regex Tester

Test regular expressions with real-time match highlighting, flags, and group captures.

How to Use Regex Tester

1Enter your regex pattern (e.g. [A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}).
2Select flags (g, i, m).
3Enter test string and view instant match highlights and captured groups.

Key Features & Benefits

Real-time regex evaluation as you type
Supports standard flags: Global (g), Case-insensitive (i), Multiline (m)
Detailed list of matched substrings, indexes, and capture groups
Clear error messaging for invalid regex syntax

About Regex Tester

Build and test JavaScript regular expressions in real-time. Test patterns with global (g), case-insensitive (i), and multiline (m) flags, inspect match groups, and view match counts.

Unlike traditional web tools that send your personal data, uploaded photos, or sensitive text to remote cloud servers, our Regex Tester operates strictly inside your client browser sandbox. This guarantees high processing speeds without network throttling, and ensures your data privacy is completely preserved.

Frequently Asked Questions

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Developer ToolsPopular Tool100% In-Browser & Private

Regex Tester

Test regular expressions with real-time match highlighting, flags, and group captures.

Regular Expression Pattern

Valid RegExp Pattern • 2 Matches Found

Test String

Match Details (2)

Match #1Index: 8

team@example.com

Match #2Index: 28

sales-team@example.com

How to Use Regex Tester

1Enter your regex pattern (e.g. [A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}).
2Select flags (g, i, m).
3Enter test string and view instant match highlights and captured groups.

Key Features & Benefits

Real-time regex evaluation as you type
Supports standard flags: Global (g), Case-insensitive (i), Multiline (m)
Detailed list of matched substrings, indexes, and capture groups
Clear error messaging for invalid regex syntax

About Regex Tester

Build and test JavaScript regular expressions in real-time. Test patterns with global (g), case-insensitive (i), and multiline (m) flags, inspect match groups, and view match counts.