RegEx Cheat Sheet & Generator

Generate common regular expressions dynamically or review anchors, quantifiers, and groupings with our interactive reference sheet.

Generated Regular Expression

/^.*$/i

Quick Templates

Choose a pattern template:

Custom Pattern Builder

Starts with:

Contains:

Ends with:

Case Insensitive (/i) Global Match (/g) Allow Numbers (\d) Allow Special Chars Allow Spaces (\s) Match Exact String Only

RegEx Quick Reference

Character Classes

. Any single character except newline \d Any digit (0-9) \D Any non-digit character \w Alphanumeric character + underscore \W Non-alphanumeric character \s Whitespace (space, tab, newline) \S Non-whitespace character

Quantifiers

* 0 or more times + 1 or more times ? 0 or 1 time (optional) {n} Exactly n times {n,} n or more times {n,m} Between n and m times

Anchors

^ Start of line / string $ End of line / string \b Word boundary \B Non-word boundary

Groups & Ranges

(x) Capture group (?:x) Non-capturing group [abc] Any character inside bracket (a, b, or c) [^abc] Any character NOT inside bracket [a-z] Any lowercase letter range x|y Matches either x or y

What is Regular Expression (RegEx)?

Regular Expressions (often abbreviated as RegEx or RegExp) are specialized character sequences that define search patterns. They are integrated into text editors, terminal commands (such as grep), and all modern programming languages.

Developers use RegEx patterns to find text configurations, replace strings, format strings, and validate web form inputs—such as verifying if an email conforms to standard formats or if a password meets complexity rules.

Using a RegEx Generator

While RegEx is extremely powerful, writing expressions from scratch can be challenging due to its abstract syntax. Characters like `?`, `*`, `+`, and `.` have special regex symbols that must be escaped using backslashes to match them literally.

This **RegEx Builder and Template Generator** simplifies the creation process. By using templates for email formats, URLs, and phone numbers, or using the input fields to compile prefix, suffix, and contains rules, you can generate patterns instantly without manually tracking brackets and symbols.

Secure Browser-Based Code Builders

All generator inputs and template calculations are processed locally. No web requests are made to external engines, making it 100% private to compile and draft your regular expressions offline.

Frequently Asked Questions

A Regular Expression (regex or regexp) is a sequence of characters that forms a search pattern. It is used in programming languages, text editors, and databases to perform pattern matching, search-and-replace, and form input validations.

By inputting starts-with, contains, and ends-with parameters, and checking restriction rules (like numbers only or spaces allowed), the generator dynamically combines anchors (^, $), character classes (\d, \s, a-z), and flags (i, g) to create the pattern.

Yes. The builder logic and regex validator code run entirely offline using standard JavaScript in your own web browser session. No data gets uploaded.