Regex Tester
Write the expression, paste your text, and watch matches highlight as you type. It lists numbered and named capture groups, the position of every match, and lets you try a replacement in the same place.
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How it works
Execution uses JavaScript own regex engine, so the syntax is ECMAScript — the same one Node and your browser run. PCRE features like lookbehind work, but recursion and backtracking verbs do not exist here.
- Live match highlighting, with index and position
- Numbered and named capture groups, listed per match
- Replace mode, supporting $1 and $<name>
- Flags g, i, m, s, u and y with an explanation of each