Developer Tools5 min read•Updated 2026-09-04
JavaScript Regular Expressions (RegEx) Cheatsheet and Tester Guide
Test regex patterns in real time, extract capture groups, and master regex flags (g, i, m, s, u).
MX
MultiToolX Technical Team
Developer Productivity Engineering
Key Takeaways
- Regular expressions provide powerful pattern matching for validation, scraping, and string manipulation.
- Common tokens: \d (digit), \w (alphanumeric), \s (whitespace), ^ (start of string), $ (end of string).
- MultiToolX evaluates JavaScript RegExp safely in-browser with live match highlighting.
1. Essential RegEx Tokens Cheat Sheet
Key tokens to remember:
- . (dot): Matches any character except newline.
- +: Matches 1 or more occurrences.
- *: Matches 0 or more occurrences.
- ?: Matches 0 or 1 occurrence (lazy quantifier).
- [a-zA-Z]: Matches any upper or lowercase letter.
Frequently Asked Questions
How do I make regex case-insensitive?
Add the 'i' flag to your regular expression (e.g. /pattern/i).
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