Test and debug regular expressions with real-time match highlighting — free, private, no signup.
Type your regular expression in the pattern field. Add flags (g, i, m, s) to control matching behavior.
Enter the text you want to match against. Matches are highlighted in real time as you type.
See all matches listed below the preview with their index positions. Errors in your regex are shown in red.
This tester uses JavaScript's built-in RegExp engine, which supports most standard regex syntax including lookaheads, backreferences, character classes, and quantifiers.
g (global) finds all matches. i ignores case. m makes ^ and $ match line boundaries. s makes . match newlines.
Use the pattern \b[\w._%+-]+@[\w.-]+\.[a-z]{2,}\b with the gi flags to match emails case-insensitively.
No. All regex matching happens in your browser using JavaScript. Your text never leaves your device.