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Test JavaScript RegExp online with flags, matches, groups, and quick presets.
Regex Tester & Visualizer helps you complete this task in seconds directly in the browser without installing extra software.
Free online regex tester for JavaScript-style patterns: toggle case insensitive and global matching, inspect captures, and compare notes with Java, Python re, SQL regex, and grep-style workflows.
Enter your pattern and choose flags (for example case insensitive or global).
Paste sample text that should match or fail.
Review each match index, full text, and numbered capture groups.
Regex Tester & Visualizer runs entirely in your browser: it takes your input, processes it on your device, and returns the result instantly — nothing is uploaded to a server. Test JavaScript RegExp online with flags, matches, groups, and quick presets.
No. This page uses the browser JavaScript RegExp engine. Syntax is often close, but Java, Python re, C#, SQL Server, and Google Sheets regex all have differences—use this tool to prototype, then port carefully.
Use the match list to confirm your pattern first. For replace, mentally substitute each match with your replacement string, or run a quick snippet in your target language.
Modern browsers support some lookbehind features, but engines vary. If a pattern fails unexpectedly, confirm support in your deployment targets.