What does this tool do

The Regex Cleaner removes or replaces text using a regular expression. Enter a regex pattern and choose to remove matches or replace them with custom text. Validates the pattern before applying; invalid regex shows an inline error. Defaults to the global flag so all matches are processed. Useful for cleaning data, stripping unwanted characters, or bulk text transformation.

How to use it

Enter text — Paste or type the text to process.
Enter pattern — Type a regular expression (e.g. \d+ for digits, \s+ for whitespace).
Replace (optional) — Leave empty to remove matches, or enter replacement text.
Set flags — Toggle global (g), case-insensitive (i), etc. as needed.
Apply — Click to run. The result appears; invalid pattern shows an error.

How it works

The pattern is validated with new RegExp() before use. If invalid, an inline error is shown and no replacement is run. If valid, the tool uses String.prototype.replace() with the chosen flags. The global (g) flag is the default so all occurrences are replaced in one pass. The result is displayed and can be copied. All processing runs client-side.

All computation runs entirely in your browser. No data is sent to any server.

Use cases & examples

Clean data — Remove extra spaces, newlines, or special characters.
Extract — Use capture groups to extract and replace (e.g. reformat dates).
Normalise — Replace variants (e.g. multiple spaces → single space).
Strip markup — Remove HTML tags or other markup.
CSV cleanup — Fix delimiters or escape sequences.

Example

Pattern \s+, replace → Collapses multiple spaces to one.
Pattern \d{3}-\d{3}-\d{4}, replace [REDACTED] → Hides phone numbers.
Pattern [^\w\s], replace empty → Removes all punctuation.

Limitations & known constraints

Pattern validated first — Invalid regex shows an error; no replacement is attempted.
ReDoS — Extremely complex patterns may cause slow execution; avoid catastrophic backtracking.
Single pass — One replace operation; chained replacements require multiple runs.
JavaScript regex — Uses JS regex flavour; some PCRE features may differ.

Regex Cleaner Guide