Regex find and replace on pasted text
Run a regular expression across pasted text and replace matches, with $1-style backreferences — right in your browser (0 uploads, works offline). No file leaves your device, which matters when the text is logs or config.
How to use it
- Paste your text.
- Enter a Find pattern (a regular expression) and a Replace string; use
$1,$2for captured groups. - The result updates live. Copy it.
FAQ
How do I do a regex find and replace online?
Paste your text, type a regular expression in Find and a replacement in Replace. Matches are replaced live in your browser with no upload; a $1 in the replacement inserts the first captured group, so (\d{4})-(\d{2})-(\d{2}) → $3/$2/$1 reformats a date.
What if my pattern is invalid?
You get a clear message explaining what is wrong with the pattern, not a raw error — and the original text is left untouched until the pattern is valid.
Is my text uploaded?
No. The replacement runs locally; nothing is sent or stored, and it works offline.
Which regex flavour is this?
JavaScript's regular expressions — the same syntax as String.replace in the browser, including named groups, lookahead and Unicode escapes.
Limits
Operates on pasted text, not files. Extremely catastrophic-backtracking patterns can be slow, since the browser runs them directly; keep patterns reasonable on large inputs.
Related
The regex tester (coming soon) explains a pattern and highlights matches; line tools handle sort and dedupe without regex.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.