Regex Tester - Free Online | FunToolX
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About this tool
Regex Tester is a free online developer tool. Test regular expressions online with match highlighting. Built for coders and engineers who want less friction. It runs entirely in your browser — no download or sign-up needed.
After opening the page, enter regular expressions and test text, and the tool will immediately display the matching results. Matching sections will be highlighted in different colors and capture groups will be listed separately. Supports regular syntax differences in different languages such as JavaScript, Python, and Java, and you can switch regular engines to test compatibility.
The tool is based on the browser-native RegExp object implementation and uses the exec method to loop all matches. For complex regexes (such as backreferences, zero-width assertions), detailed matching procedures and backtracking information are displayed. Some tools also provide regular syntax highlighting and error prompts.
Suitable for developers to debug regular expressions and verify whether complex patterns are correct. It is more efficient than repeatedly testing in code, and you can visually see the matching results and capture group content.
Regular expression online testing tool, which verifies regular matching results in real time, supports multiple regular grammars, and visualizes highlighting matching content and capture groups.