Test and debug regular expressions online for free with real-time matching and group extraction. Supports JavaScript regex syntax. No signup required.
First time here? Enter your regex pattern Your input is processed locally and disappears when you close the tab.
Regular expressions are one of the most powerful tools in a developer's kit, but a single stray character can quietly break a pattern. Our free Regex Tester is a real-time regex tester online that highlights matches inside your sample text the instant you type, so you can build and fix expressions by seeing exactly what they capture rather than guessing.
Powered by JavaScript's native RegExp engine, this regular expression tool is fully compatible with the javascript regex used across Node, browsers, and most modern languages. Toggle the global (g), case-insensitive (i), multiline (m), and dotAll (s) flags on the fly, and every match appears as a numbered regex match tester result with its position and extracted capture groups. Turn on replace mode to preview substitutions live, referencing groups with $1, $2, and beyond, making it a practical regex pattern tester for validating emails, cleaning log files, rewriting URLs, or extracting structured data. One-click buttons copy your pattern, matches, or replaced output.
Because everything is computed locally, none of your patterns or test data is ever uploaded and sensitive strings stay on your machine. Pair the tester with our Case Converter for text transformations, the Slug Generator for URL-safe strings, and the JSON Formatter for inspecting API data. When your scripts are ready, shrink them with the JavaScript Minifier before you ship.
Enter your regex pattern
Type or paste test text
See matches highlighted in real time
View capture groups and match details