Which regex flavor does this tool use?

This tool uses JavaScript's native RegExp engine, which supports all modern features including named capture groups (? ), lookbehind assertions (?<=), Unicode property escapes (\p{}), and the dotAll (s) flag.

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

Different languages have slightly different regex implementations. Python, Java, and .NET may handle features like lookbehinds, possessive quantifiers, or Unicode differently. This tool matches JavaScript's behavior exactly.

Is my data safe when using the Regex Tester?

Yes. All computations, parsing, and transformations occur locally inside your browser via client-side JavaScript. No input data is sent to external servers.

Is the Regex Tester completely free?

Yes. QuizOxa Tools is 100% free with no subscription, account creation, or rate limits required.

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Developer Client-Side

Free Online Regex Tester & Debugger

Write and test regular expressions with instant visual feedback. See matches highlighted in real-time as you type, inspect capture groups and their values, toggle flags (global, case-insensitive, multiline, dotAll), and view detailed match information including indices and named groups. Essential for building and debugging regex patterns for form validation, text parsing, log analysis, and data extraction.

100% In-Browser Privacy Instant Zero-Lag Execution Zero Data Uploaded

Regular expression

//g

Flags

Test string

Matches (3)

Match 1index 14

[email protected]

Group 1: johnGroup 2: example.com

Match 2index 34

[email protected]

Group 1: supportGroup 2: quizoxa.com

Match 3index 78

[email protected]

Group 1: adminGroup 2: test.org

How to Use Regex Tester

Input Your Data

Paste or type your input into the workspace above, or upload a target file directly.

Configure Settings

Select desired formatting options, conversion rules, or target units suited for your project.

Instant Processing

Execution completes in milliseconds right inside your browser memory with zero network latency.

Export & Copy

Use one-click copy to move the processed output to your clipboard or download files locally.

Key Highlights & Privacy Guarantee

Zero Server Storage

Your data is processed strictly in client-side RAM using WebAssembly and standard JavaScript APIs. No data packets or credentials are sent to our backend.

High-Speed Execution

By removing server round-trips, transformations occur in under a millisecond, optimizing Core Web Vitals and eliminating processing queues.

Free with Zero Limits

No subscription tiers, no hidden credit systems, and no registration walls. Run unlimited conversions and utilities whenever needed.

In-Depth Developer Guides

20 min read•General

Complete Regex Cheat Sheet: Regular Expressions Syntax, Patterns & Examples

Master Regular Expressions with this ultimate Regex Cheat Sheet. Learn anchors, quantifiers, character classes, lookaheads, lookbehinds, flags, and copy-paste common regex patterns for email, URL, IP, phone, and password validation.

Read Full Guide

Frequently Asked Questions

This tool uses JavaScript's native RegExp engine, which supports all modern features including named capture groups (?<name>), lookbehind assertions (?<=), Unicode property escapes (\p{}), and the dotAll (s) flag.