Regex Tester

Test regular expressions, inspect capture groups, and replace text.

JavaScript regular expressions. Enter a pattern without / delimiters. Positions are zero-based UTF-16 indices; ∅ marks an empty match.

Pattern

Flags

g all matches · i ignore case · m multiline ^/$ · s dot includes line breaks · u Unicode · v Unicode sets (exclusive with u) · y sticky

Input text

Replace with an empty stringReplacement

Replacement: $$, $&, $1–$99, $<name>, $` (prefix), $' (suffix). Without g, only the first match is replaced.

Runs in a Worker with a 1-second limit. Input/replacement: 100,000 characters each; pattern: 5,000; matches: 1,000; output: 1,000,000.

Text is processed only in your browser.