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Apply JavaScript regex replacements locally, inspect which matches were changed, and keep source text out of external services.
What this tool helps you answer
Apply JavaScript regex find-and-replace locally, preview the matched segments, and inspect the transformed output before copying it anywhere else.
Next step
Use this page when you need regex-powered text replacement without opening a general code editor or mixing the task into a broader text-cleanup pipeline.
Editorial review
This page combines the live tool, input guidance, worked examples, and operating limits so Regex Replace Tool stays useful even before users interact with the calculator.
Reviewed by Klartext Tools against the current Regex Replace Tool workflow on 2026-03-12.
Last updated:
Use with judgment
Page scope
A simple case-insensitive global replacement across repeated words.
Every cat or dog label is replaced with pet while the preview table shows the matched segments.
Use capture groups to rearrange structured values during replacement.
Transforms ISO dates into month/day/year order using numbered captures.
Use this page for JavaScript-style regex find-and-replace work when you want the replacement count and output preview visible.
Use the same JavaScript regex syntax and flags you would use in browser code or String.replace.
Work with a realistic sample first if the full document is large or risky to transform blindly.
Plain text works, and capture references like $1 or named groups also follow JavaScript replacement semantics.
Check the match count and output before copying the transformed text into the next system.
Use these examples to test common replace workflows before pasting real text.
A simple case-insensitive global replacement across repeated words.
Sample inputs
Sample outcome: Every cat or dog label is replaced with pet while the preview table shows the matched segments.
Use capture groups to rearrange structured values during replacement.
Sample inputs
Sample outcome: Transforms ISO dates into month/day/year order using numbered captures.
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