IconVault's Regex Tester is a live workbench for regular expressions. Type your pattern, toggle flags like g, i, m, s, u and y, and paste a test string - matches are highlighted instantly, each match is listed with its index, and captured groups are shown one by one so you can see exactly what your pattern grabbed.

It runs entirely in your browser using the real JavaScript RegExp engine, so what you test here behaves exactly like it will in your code. Invalid patterns get a clear red error message instead of silent failure, and you can copy the pattern as a ready-to-paste /pattern/flags literal. A built-in replace mode lets you test find-and-replace with $1-style backreferences before touching your code, a searchable cheat-sheet inserts common tokens with one click, and a share button encodes pattern, flags and test text into a linkable URL. Every visitor gets 5 free tests - IconVault Pro ($12/year) unlocks unlimited use of every developer tool.