Regex Tester
Test a regular expression against text with highlighted matches and capture groups.
Private by design. Your input never leaves this browser. Conversions run locally on your device.
What this tool handles
- Matches or replaces, with the g, i, m, s, u, v, y and d flags.
- Shows every match with its index and its capture groups.
- The pattern runs in a Web Worker that is killed after 750 ms, so catastrophic backtracking cannot freeze the tab.
- Replacement supports $1, $2 and named group references.
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