What is a regular expression?

A regular expression (regex) is a pattern that describes a set of strings, used for searching, matching, and replacing text.

What do the flags g, i, m mean?

g = global (find all matches), i = case-insensitive, m = multiline (^ and $ match line boundaries).

Is my data sent to a server?

No. All regex testing happens locally in your browser. No data is transmitted.

Home / Tools / Text & Developer Tools / Regex Tester

Developer Tool

Regex Tester

Test and debug regular expressions with real-time match highlighting, capture groups, and replace. Preset patterns included.

Pattern

/ /

Test String

Matches

Replace With

Quick Presets

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