Pattern Matching & Text Prep
RegEx Tester & Cheat Sheet
Test, debug, and verify regular expressions right in your browser. Inspect capture groups, test replacement strings, and explore common presets without sending sensitive log data to external servers.
Pure client-side RegExp engine, zero server transmission
💡 Common Regex Cheat Sheet
How it works
Standard ECMAScript Regular Expression Engine Guide
Many online regex testing services transmit your test strings and application logs to remote servers. Testing with real logs that contain API keys, emails, or credentials presents high compliance risks.
Dev Desk Regex Tester executes directly inside your browser's native JavaScript RegExp engine. Pattern matching, capture group extraction, and replacement preview happen strictly offline.
Syntax: /pattern/flags supporting capture groups (...), non-capturing (?:...), lookaheads (?=...), and metacharacters \d, \w, \s.
FAQ
RegEx Tester & Cheat Sheet · FAQ
Is my test data uploaded to any server?
Never. All regex compilation, matching, and replacement occur 100% in your local browser memory. You can use it completely offline.
Which flags are supported?
Standard flags: g (global), i (ignoreCase), m (multiline), s (dotAll), and u (unicode).
How do I reference capture groups in the replacement?
Use $1, $2, etc., to reference matched parentheses groups, or $& to insert the entire matched substring.