Does this regex tester support JavaScript regex syntax?

Yes. It uses the browser's JavaScript regex engine, so the pattern behavior matches normal JavaScript usage. If the browser rejects a pattern or flag, the tool shows the compiler error directly.

Can I test regex flags like g and i?

Yes. Enter the flags in the flags field and the tool will compile the pattern with those options. That lets you inspect global matching, case-insensitive matching, multiline behavior, and more.

Does the regex tester upload my sample text?

No. Testing happens locally in your browser, so your sample text and regex stay on your device.

What happens if the pattern is invalid?

The tool shows the JavaScript regex compiler error so you can correct the pattern or flags and test again.

Can I inspect capture groups?

Yes. Each match includes any captured groups, which makes it easier to debug extraction patterns and grouping logic.

Regex Tester

Test JavaScript regular expressions instantly with browser-side execution, optional flags, match listings, and captured group inspection. Perfect for debugging patterns, validating search rules, and teaching regex behavior safely.

regex

tester

pattern

Share this tool:

Quick Presets

Examples for common regex testing workflows

Regex Pattern & Sample Text

Paste a pattern, optional flags, and sample text to test the regex locally in your browser.

Regex Pattern

Characters: 0

Lines: 0

Bytes: 0

Flags

Supported JavaScript flags like g, i, m, s, u, and y.

Sample Text

Characters: 0

Lines: 0

Bytes: 0

Match Scope

All matchesFind every match in the sample text and list each resultFirst matchStop after the first match when you only need a quick check

How it works: This tester compiles your JavaScript regex locally, applies the selected match scope, and lists each match with index positions and captured groups. Nothing is sent to a server.

Continue Your Code Journey

More tools you might find useful

Regex Escape

Escape text for safe insertion into regular expressions

Glob to Regex Converter

Convert glob patterns into JavaScript regex source

IBAN Generator

Generate valid International Bank Account Numbers for testing

Markdown Linter

Check markdown for syntax and style issues

🌈 Browse More Tools

All Code Tools All Tools

Complete Guide: Regex Tester

Everything you need to know about using Regex Tester effectively

Related Tools

More tools you might find useful

Featured

CSV to JSON Converter

Transform CSV data into JSON structures

Analyze IPv4 CIDR ranges and derived network details

Calculate IPv4 subnet ranges and host details

Generate starter Dockerfiles for common app stacks

docker

dockerfile

container

Credit Card Generator

Generate valid dummy credit card numbers for testing

Calculate and verify SHA checksums for text or files

Validate standard crontab expressions with next-run previews

cron

crontab

validator

.htaccess Redirect Generator

Create Apache .htaccess redirect rules and URL rewriting

htaccess

redirect

apache

Related Collections

Collections that include this tool - discover more tools in these curated collections

Code Formatting & Beautifying Tools

Professional code formatting and developer utility tools. Format HTML, SQL, YAML, and JSON, test regex, escape patterns, convert globs, or turn cURL commands into JavaScript Fetch.

View collection