Which regex engine does the Regex Tester use?

The tester uses JavaScript's native RegExp engine (ECMAScript standard), which is compatible with most modern programming languages for common regex patterns.

Can I test with multiple regex flags at once?

Yes. Enable any combination: g (global), i (case-insensitive), m (multiline), s (dotAll), and u (Unicode mode). Each flag can be toggled independently.

Does the tester highlight all matches in real time?

Yes. All matches are highlighted in the test string as you type the pattern, with no need to click a button. Each capture group is shown separately in the matches panel.

Can I use the Regex Tester to learn regular expressions?

Yes. The tool explains what each part of your pattern matches and shows capture groups visually — useful for learning and debugging complex patterns.

Does Regex Tester log or store the data I paste into it?

No. Regex Tester processes everything locally in your browser. Nothing is sent to a server, logged, or stored. Your code, secrets, and data never leave your machine.

Which browsers are compatible with Regex Tester?

Regex Tester works in all modern evergreen browsers: Chrome 90+, Firefox 88+, Edge 90+, and Safari 14+. Internet Explorer is not supported.

How does Regex Tester work?

Regex Tester analyses the content, URL, or data you provide and returns a detailed report with actionable findings. All analysis runs in your browser — no server upload required.

Is Regex Tester free to use?

Yes, Regex Tester is 100% free with no usage limits, no watermarks, and no hidden charges. The platform is supported by non-intrusive advertising so all tools stay free for everyone.

Do I need to create an account to use Regex Tester?

No account or registration is required. Open Regex Tester and start immediately — no email, no sign-up, no personal information needed.

Is my data safe when using Regex Tester?

Yes. Regex Tester runs entirely in your browser using client-side JavaScript. Your files and data never leave your device and are never transmitted to our servers.

Does Regex Tester work on mobile and tablet devices?

Yes. Regex Tester is fully responsive and tested on smartphones, tablets, and all major desktop browsers (Chrome, Firefox, Safari, and Edge). The interface adapts automatically to any screen size.

Regex Tester

Test and debug regular expressions

FreeNo sign-upDeveloper Tools →

Regex Tester is a free, browser-based web development and coding tool. Test regular expressions with real-time match highlighting. Supports JavaScript, Python, and PCRE regex flavors.

Web developers, software engineers, and DevOps professionals use Regex Tester every day to save time and skip the overhead of desktop software or paid services. No installation, no account, and no technical knowledge required — just paste your content into Regex Tester and get results in seconds. Your files never leave your browser — full privacy by design.

Regex Tester

Pattern

//g

Flags

Test String

Matches highlighted3 matches

Hello World! Contact us at hello@example.com or support@test.io Visit https://example.com or http://test.org for more info. IP: 192.168.1.1, Date: 12/31/2024, Color: #FF5733 or #fff Another email: john.doe+tag@company.co.uk

#1hello@example.com@27

#2support@test.io@48

#3john.doe+tag@company.co.uk@197

How to use Regex Tester

Enter regex

Type your regular expression pattern.

Paste test string

Enter the text to test against.

View matches

See all matches highlighted in real time.

Use Cases

Debugging and validating data formats during API development
Preparing test fixtures and sample payloads
Encoding and decoding data for integrations and authentication flows
Formatting and linting configuration files before deployment

Key Benefits

100% free with no usage limits, watermarks, or hidden fees
No account or sign-up required — use it instantly
Works in all modern browsers on desktop, tablet, and mobile
Privacy-first: all processing runs locally, files never leave your device
Actionable insights with clear, readable output
Detailed breakdown with specific recommendations

Regex Tester

How to use Regex Tester

Enter regex

Paste test string

View matches

Use Cases

Key Benefits

Frequently Asked Questions

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