Local developer utility

Regular Expression Tester

Test JavaScript regular expressions with flags, match positions, and capture groups. Your input stays in your browser while you work.

Regex Tester🔒 Processed locally

How to use Regex Tester

Complete the labeled fields above, choose an action, and inspect the result before copying or downloading it.

Processing runs locally in this browser. No input is uploaded or sent to a conversion service.

Pattern preset
Regular expression: ([a-z]+)
Regex flags: g: all matches · i: ignore case · m: multiline · s: dot matches newline · u/v: Unicode · y: sticky · d: indices
Operation
Replacement text: Use $1 for a capture group, $<name> for a named group, or $& for the whole match.
Test text: Paste the text to search

Line Sorter — Sort lines alphabetically with configurable direction and duplicate removal.
String Escape / Unescape — Escape text as a JSON string or decode JSON string escapes.
UTF-8 Byte Counter — Count UTF-8 bytes, Unicode code points, and UTF-16 code units.
Zero-width Character Detector — Locate invisible formatting characters and optionally remove them.