Enter a pattern, choose flags, and test against your text. Matches are highlighted inline. Capture groups are listed per match. Nothing leaves your browser.
Write a regular expression, paste your test string, and see every match highlighted in real time, including numbered capture groups and their extracted values. The engine is the browser's native JavaScript RegExp, so behaviour matches exactly what your JS or TypeScript code will do at runtime.
Flags (g, i, m, s, u) are togglable with checkboxes, and a table below the input lists each match with its index and the value of every numbered or named capture group.
No. Every operation runs inside your browser tab using JavaScript and WebAssembly. Your file is read into memory on your own device, processed there, and the result is offered as a local download. Nothing is transmitted to Sunasty or any third party. You can verify it yourself: open your browser DevTools, go to the Network tab, and watch, no request carries your file.
The tool uses the browser's built-in JavaScript RegExp engine (ECMAScript 2023+), including named capture groups (?<name>...), lookaheads, lookbehinds, and Unicode property escapes (\p{L} etc.) with the u flag.
Yes, below the highlighted input, a table lists every match with its index, full match, and the value of each numbered or named capture group.
Yes, once the page has loaded. Because the processing happens on your device, you can disconnect from the network and the tool keeps working. This is the clearest proof that your data never leaves your machine.
It is completely free and requires no sign-up. There are no watermarks, no daily limits and no tracking cookies needed to use the tool.