Find and Replace — Regex, Highlight, Undo

Yes. Toggle the Regex mode checkbox to use full JavaScript regular expression syntax in the Find field. Capture groups and backreferences are supported in replacements.

Yes. Every Replace All or Replace Next operation is pushed to an undo stack. Click Undo to revert the last replacement, and keep clicking to undo further.

Whole Word mode adds word boundary markers so your search only matches complete words, not substrings. For example, searching for "the" will not match "there".

The tool runs in your browser, so it can handle texts of several hundred thousand characters. Very large files may slow the regex engine, especially with complex patterns.

No. Everything runs locally in your browser. No text is uploaded or stored anywhere.