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Advanced Visual Regex Builder v3.8

Build, import, explain, test and share regex visually.

Regex library

Regex Library

Browse all regex guides, examples, concepts and categories available on CreateRegex.

15 pages 50 examples 15 concepts 93 guides

Categories

Advanced Regex 11 Api 10 Compatibility 11 Data & Formats 23 Design 12 Examples 50 Guides 93 Identity 11 Javascript 11 Key Concepts 15 Learning 112 Networking 26 Reference 13 Regex Engine 11 Security 12 SEO 12 Telecommunications 13 Tutorial 12 Validation 126 Web Development 46

Tags

account 11 Alpha Channel 2 Alternation (|) 2 Anchors 13 API 10 ASCII 1 Assertion (^ $ \b) 11 Authentication 12 Basics / Beginner 14 boundaries 1 Browser 1 Calendar 13 Capturing 1 Character Classes 4 characters 2 cheatsheet 13 CIDR 13 classes 2 CMS 12 Compatibility 22 content 12 CSS 12 Data Validation 22 Database 10 Date 13 design system 12 DNS 13 Domain 13 E.164 13 Email 8 frontend 12 groups 15 HEX Color 12 Identifier 10 Input Validation 44 International 16 IP Address 13 ISO-8601 13 Javascript 22 Learn Regex 12 Length 2 limit 2 Login 12 Logs 10 lookarounds 1 Lookbehind (?<=...) 12 Mobile Phone 13 negative lookbehind 2 Networking 13 password 12 PCRE 11 Phone Number 13 positive lookbehind 2 Private network 2 Profile 11 Punycode 13 Quantifiers (* + ?) 15 Regex Engines 12 Repetition 1 restrictive 1 security 12 seo 12 simple pattern 3 slug 12 Strict Validation 2 subdomain 13 Sub-Domains 2 syntax 13 Timestamps 13 TLD 13 tokens 13 tutorial 12 Unicode 24 URL-safe 12 username 11 UUID 15 validation 17 verification 1 Web - HTTP/HTTPS Links 11

All Regex Guides

Advanced Regex

Page 1

JavaScript Lookbehind Page

Concept 3

Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept

Guide 7

What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide

Api

Page 1

UUID Regex Page

Example 4

Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example

Guide 5

What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide

Compatibility

Page 1

JavaScript Regex vs PCRE Page

Concept 3

Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 7

What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

Data & Formats

Page 2

Date Regex Page UUID Regex Page

Example 9

DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example

Guide 12

Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide

Design

Page 1

Hex Color Regex Page

Example 6

Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example

Guide 5

What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide

Examples

Example 50

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example Simple email regex Email Regex Example More restrictive email regex Email Regex Example Simple URL regex URL Regex Example HTTPS-only URL regex URL Regex Example Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example Private IPv4 ranges IP Address Regex Example IPv4 with CIDR IP Address Regex Example Basic IPv6 IP Address Regex Example Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guides

Guide 93

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide Why use an email regex? Email Regex Guide What makes email validation difficult? Email Regex Guide Common email validation rules Email Regex Guide Regex validation vs real email verification Email Regex Guide Should you use a strict or simple email regex? Email Regex Guide Why use a URL regex? URL Regex Guide What is a valid URL? URL Regex Guide HTTP vs HTTPS URL validation URL Regex Guide Should a regex validate URLs completely? URL Regex Guide Common URL validation mistakes URL Regex Guide When to use URL regex validation URL Regex Guide Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide Why validate IP addresses with regex? IP Address Regex Guide IPv4 vs IPv6 IP Address Regex Guide What makes IPv6 validation difficult? IP Address Regex Guide CIDR notation explained IP Address Regex Guide Private vs public IP addresses IP Address Regex Guide Can regex verify that an IP address exists? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide How to learn regex step by step Regex Tutorial Guide Start with literal text Regex Tutorial Guide Use character classes for flexibility Regex Tutorial Guide Add quantifiers to repeat patterns Regex Tutorial Guide Use groups to organize your regex Regex Tutorial Guide Test regex patterns often Regex Tutorial Guide Common beginner mistakes Regex Tutorial Guide What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

Identity

Page 1

Username Regex Page

Example 6

Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example

Guide 4

What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide

Javascript

Page 1

JavaScript Lookbehind Page

Concept 3

Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept

Guide 7

What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide

Key Concepts

Concept 15

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept Start with exact text Regex Tutorial Concept Use character classes Regex Tutorial Concept Add repetition Regex Tutorial Concept Test often Regex Tutorial Concept Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Learning

Page 4

Regex Cheatsheet Page Regex Tutorial Page JavaScript Lookbehind Page JavaScript Regex vs PCRE Page

Concept 15

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept Start with exact text Regex Tutorial Concept Use character classes Regex Tutorial Concept Add repetition Regex Tutorial Concept Test often Regex Tutorial Concept Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 93

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide Why use an email regex? Email Regex Guide What makes email validation difficult? Email Regex Guide Common email validation rules Email Regex Guide Regex validation vs real email verification Email Regex Guide Should you use a strict or simple email regex? Email Regex Guide Why use a URL regex? URL Regex Guide What is a valid URL? URL Regex Guide HTTP vs HTTPS URL validation URL Regex Guide Should a regex validate URLs completely? URL Regex Guide Common URL validation mistakes URL Regex Guide When to use URL regex validation URL Regex Guide Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide Why validate IP addresses with regex? IP Address Regex Guide IPv4 vs IPv6 IP Address Regex Guide What makes IPv6 validation difficult? IP Address Regex Guide CIDR notation explained IP Address Regex Guide Private vs public IP addresses IP Address Regex Guide Can regex verify that an IP address exists? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide How to learn regex step by step Regex Tutorial Guide Start with literal text Regex Tutorial Guide Use character classes for flexibility Regex Tutorial Guide Add quantifiers to repeat patterns Regex Tutorial Guide Use groups to organize your regex Regex Tutorial Guide Test regex patterns often Regex Tutorial Guide Common beginner mistakes Regex Tutorial Guide What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

Networking

Page 2

IP Address Regex Page Domain Name Regex Page

Example 11

Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example Private IPv4 ranges IP Address Regex Example IPv4 with CIDR IP Address Regex Example Basic IPv6 IP Address Regex Example Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example

Guide 13

Why validate IP addresses with regex? IP Address Regex Guide IPv4 vs IPv6 IP Address Regex Guide What makes IPv6 validation difficult? IP Address Regex Guide CIDR notation explained IP Address Regex Guide Private vs public IP addresses IP Address Regex Guide Can regex verify that an IP address exists? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide

Reference

Page 1

Regex Cheatsheet Page

Concept 5

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept

Guide 7

What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide

Regex Engine

Page 1

JavaScript Regex vs PCRE Page

Concept 3

Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 7

What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

Security

Page 1

Password Regex Page

Example 4

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example

Guide 7

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide

SEO

Page 1

Slug Regex Page

Example 5

Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 6

What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

Telecommunications

Page 1

Phone Number Regex Page

Example 5

Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example

Guide 7

Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide

Tutorial

Page 1

Regex Tutorial Page

Concept 4

Start with exact text Regex Tutorial Concept Use character classes Regex Tutorial Concept Add repetition Regex Tutorial Concept Test often Regex Tutorial Concept

Guide 7

How to learn regex step by step Regex Tutorial Guide Start with literal text Regex Tutorial Guide Use character classes for flexibility Regex Tutorial Guide Add quantifiers to repeat patterns Regex Tutorial Guide Use groups to organize your regex Regex Tutorial Guide Test regex patterns often Regex Tutorial Guide Common beginner mistakes Regex Tutorial Guide

Validation

Page 11

Password Regex Page Email Regex Page URL Regex Page Phone Number Regex Page Username Regex Page Date Regex Page IP Address Regex Page UUID Regex Page Hex Color Regex Page Domain Name Regex Page Slug Regex Page

Example 50

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example Simple email regex Email Regex Example More restrictive email regex Email Regex Example Simple URL regex URL Regex Example HTTPS-only URL regex URL Regex Example Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example Private IPv4 ranges IP Address Regex Example IPv4 with CIDR IP Address Regex Example Basic IPv6 IP Address Regex Example Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 65

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide Why use an email regex? Email Regex Guide What makes email validation difficult? Email Regex Guide Common email validation rules Email Regex Guide Regex validation vs real email verification Email Regex Guide Should you use a strict or simple email regex? Email Regex Guide Why use a URL regex? URL Regex Guide What is a valid URL? URL Regex Guide HTTP vs HTTPS URL validation URL Regex Guide Should a regex validate URLs completely? URL Regex Guide Common URL validation mistakes URL Regex Guide When to use URL regex validation URL Regex Guide Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide Why validate IP addresses with regex? IP Address Regex Guide IPv4 vs IPv6 IP Address Regex Guide What makes IPv6 validation difficult? IP Address Regex Guide CIDR notation explained IP Address Regex Guide Private vs public IP addresses IP Address Regex Guide Can regex verify that an IP address exists? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

Web Development

Page 4

URL Regex Page Hex Color Regex Page Domain Name Regex Page Slug Regex Page

Example 19

Simple URL regex URL Regex Example HTTPS-only URL regex URL Regex Example Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 23

Why use a URL regex? URL Regex Guide What is a valid URL? URL Regex Guide HTTP vs HTTPS URL validation URL Regex Guide Should a regex validate URLs completely? URL Regex Guide Common URL validation mistakes URL Regex Guide When to use URL regex validation URL Regex Guide What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

Browse by tag

account

Page 1

Username Regex Page

Example 6

Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example

Guide 4

What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide

Alpha Channel

Example 1

Hex color with alpha Hex Color Regex Example

Guide 1

Hex colors with alpha transparency Hex Color Regex Guide

Alternation (|)

Concept 1

Groups and alternatives Regex Cheatsheet Concept

Guide 1

Groups, alternation and anchors Regex Cheatsheet Guide

Anchors

Page 1

Regex Cheatsheet Page

Concept 5

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept

Guide 7

What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide

API

Page 1

UUID Regex Page

Example 4

Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example

Guide 5

What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide

ASCII

Guide 1

ASCII usernames vs Unicode usernames Username Regex Guide

Assertion (^ $ \b)

Page 1

JavaScript Lookbehind Page

Concept 3

Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept

Guide 7

What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide

Authentication

Page 1

Password Regex Page

Example 4

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example

Guide 7

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide

Basics / Beginner

Page 1

Regex Tutorial Page

Example 2

Basic IPv6 IP Address Regex Example Basic slug Slug Regex Example

Concept 4

Start with exact text Regex Tutorial Concept Use character classes Regex Tutorial Concept Add repetition Regex Tutorial Concept Test often Regex Tutorial Concept

Guide 7

How to learn regex step by step Regex Tutorial Guide Start with literal text Regex Tutorial Guide Use character classes for flexibility Regex Tutorial Guide Add quantifiers to repeat patterns Regex Tutorial Guide Use groups to organize your regex Regex Tutorial Guide Test regex patterns often Regex Tutorial Guide Common beginner mistakes Regex Tutorial Guide

boundaries

Concept 1

Anchors and boundaries Regex Cheatsheet Concept

Browser

Guide 1

Browser compatibility considerations JavaScript Lookbehind Guide

Calendar

Page 1

Date Regex Page

Example 5

DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example

Guide 7

Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide

Capturing

Guide 1

Lookbehind vs capturing groups JavaScript Lookbehind Guide

Character Classes

Concept 2

Character classes Regex Cheatsheet Concept Use character classes Regex Tutorial Concept

Guide 2

Character classes explained Regex Cheatsheet Guide Use character classes for flexibility Regex Tutorial Guide

characters

Concept 1

Character classes Regex Cheatsheet Concept

Guide 1

Character classes explained Regex Cheatsheet Guide

cheatsheet

Page 1

Regex Cheatsheet Page

Concept 5

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept

Guide 7

What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide

CIDR

Page 1

IP Address Regex Page

Example 5

Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example Private IPv4 ranges IP Address Regex Example IPv4 with CIDR IP Address Regex Example Basic IPv6 IP Address Regex Example

Guide 7

Why validate IP addresses with regex? IP Address Regex Guide IPv4 vs IPv6 IP Address Regex Guide What makes IPv6 validation difficult? IP Address Regex Guide CIDR notation explained IP Address Regex Guide Private vs public IP addresses IP Address Regex Guide Can regex verify that an IP address exists? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide

classes

Concept 1

Character classes Regex Cheatsheet Concept

Guide 1

Character classes explained Regex Cheatsheet Guide

CMS

Page 1

Slug Regex Page

Example 5

Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 6

What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

Compatibility

Page 2

JavaScript Lookbehind Page JavaScript Regex vs PCRE Page

Concept 6

Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 14

What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

content

Page 1

Slug Regex Page

Example 5

Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 6

What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

CSS

Page 1

Hex Color Regex Page

Example 6

Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example

Guide 5

What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide

Data Validation

Page 1

Date Regex Page

Example 7

DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example

Guide 14

Common username validation rules Username Regex Guide What regex cannot validate Username Regex Guide Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide Why validate IP addresses with regex? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide Common hex color validation mistakes Hex Color Regex Guide Common domain validation mistakes Domain Name Regex Guide Slug validation vs slug generation Slug Regex Guide

Database

Page 1

UUID Regex Page

Example 4

Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example

Guide 5

What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide

Date

Page 1

Date Regex Page

Example 5

DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example

Guide 7

Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide

design system

Page 1

Hex Color Regex Page

Example 6

Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example

Guide 5

What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide

DNS

Page 1

Domain Name Regex Page

Example 6

Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example

Guide 6

What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide

Domain

Page 1

Domain Name Regex Page

Example 6

Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example

Guide 6

What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide

E.164

Page 1

Phone Number Regex Page

Example 5

Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example

Guide 7

Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide

Email

Page 1

Email Regex Page

Example 2

Simple email regex Email Regex Example More restrictive email regex Email Regex Example

Guide 5

Why use an email regex? Email Regex Guide What makes email validation difficult? Email Regex Guide Common email validation rules Email Regex Guide Regex validation vs real email verification Email Regex Guide Should you use a strict or simple email regex? Email Regex Guide

frontend

Page 1

Hex Color Regex Page

Example 6

Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example

Guide 5

What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide

groups

Page 1

Regex Cheatsheet Page

Concept 5

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept

Guide 9

What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide Use groups to organize your regex Regex Tutorial Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide

HEX Color

Page 1

Hex Color Regex Page

Example 6

Short hex color Hex Color Regex Example Long hex color Hex Color Regex Example Short or long hex color Hex Color Regex Example Hex color with alpha Hex Color Regex Example Any CSS hex color Hex Color Regex Example Hex color without # Hex Color Regex Example

Guide 5

What is a hex color? Hex Color Regex Guide Short vs long hex colors Hex Color Regex Guide Hex colors with alpha transparency Hex Color Regex Guide Common hex color validation mistakes Hex Color Regex Guide When to use a hex color regex Hex Color Regex Guide

Identifier

Page 1

UUID Regex Page

Example 4

Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example

Guide 5

What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide

Input Validation

Page 4

Password Regex Page Email Regex Page Phone Number Regex Page Username Regex Page

Example 17

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example Simple email regex Email Regex Example More restrictive email regex Email Regex Example Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example

Guide 23

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide Why use an email regex? Email Regex Guide What makes email validation difficult? Email Regex Guide Common email validation rules Email Regex Guide Regex validation vs real email verification Email Regex Guide Should you use a strict or simple email regex? Email Regex Guide Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide

International

Page 1

Phone Number Regex Page

Example 6

Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example International username Username Regex Example

Guide 9

Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide Internationalized domain names Domain Name Regex Guide Unicode slugs and international websites Slug Regex Guide

IP Address

Page 1

IP Address Regex Page

Example 5

Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example Private IPv4 ranges IP Address Regex Example IPv4 with CIDR IP Address Regex Example Basic IPv6 IP Address Regex Example

Guide 7

Why validate IP addresses with regex? IP Address Regex Guide IPv4 vs IPv6 IP Address Regex Guide What makes IPv6 validation difficult? IP Address Regex Guide CIDR notation explained IP Address Regex Guide Private vs public IP addresses IP Address Regex Guide Can regex verify that an IP address exists? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide

ISO-8601

Page 1

Date Regex Page

Example 5

DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example

Guide 7

Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide

Javascript

Page 2

JavaScript Lookbehind Page JavaScript Regex vs PCRE Page

Concept 6

Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 14

What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

Learn Regex

Page 1

Regex Tutorial Page

Concept 4

Start with exact text Regex Tutorial Concept Use character classes Regex Tutorial Concept Add repetition Regex Tutorial Concept Test often Regex Tutorial Concept

Guide 7

How to learn regex step by step Regex Tutorial Guide Start with literal text Regex Tutorial Guide Use character classes for flexibility Regex Tutorial Guide Add quantifiers to repeat patterns Regex Tutorial Guide Use groups to organize your regex Regex Tutorial Guide Test regex patterns often Regex Tutorial Guide Common beginner mistakes Regex Tutorial Guide

Length

Example 2

Username with length limit Username Regex Example Fixed-length slug Slug Regex Example

limit

Example 2

Username with length limit Username Regex Example Fixed-length slug Slug Regex Example

Login

Page 1

Password Regex Page

Example 4

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example

Guide 7

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide

Logs

Page 1

UUID Regex Page

Example 4

Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example

Guide 5

What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide

lookarounds

Concept 1

Lookarounds Regex Cheatsheet Concept

Lookbehind (?<=...)

Page 1

JavaScript Lookbehind Page

Concept 3

Positive lookbehind JavaScript Lookbehind Concept Negative lookbehind JavaScript Lookbehind Concept Compatibility JavaScript Lookbehind Concept

Guide 8

What is a lookbehind assertion? JavaScript Lookbehind Guide Positive vs negative lookbehind JavaScript Lookbehind Guide Why use lookbehind in JavaScript? JavaScript Lookbehind Guide Common lookbehind use cases JavaScript Lookbehind Guide Browser compatibility considerations JavaScript Lookbehind Guide Lookbehind vs capturing groups JavaScript Lookbehind Guide When not to use lookbehind JavaScript Lookbehind Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide

Mobile Phone

Page 1

Phone Number Regex Page

Example 5

Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example

Guide 7

Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide

negative lookbehind

Concept 1

Negative lookbehind JavaScript Lookbehind Concept

Guide 1

Positive vs negative lookbehind JavaScript Lookbehind Guide

Networking

Page 1

IP Address Regex Page

Example 5

Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example Private IPv4 ranges IP Address Regex Example IPv4 with CIDR IP Address Regex Example Basic IPv6 IP Address Regex Example

Guide 7

Why validate IP addresses with regex? IP Address Regex Guide IPv4 vs IPv6 IP Address Regex Guide What makes IPv6 validation difficult? IP Address Regex Guide CIDR notation explained IP Address Regex Guide Private vs public IP addresses IP Address Regex Guide Can regex verify that an IP address exists? IP Address Regex Guide When to use IP address regex validation IP Address Regex Guide

password

Page 1

Password Regex Page

Example 4

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example

Guide 7

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide

PCRE

Page 1

JavaScript Regex vs PCRE Page

Concept 3

Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 7

What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

Phone Number

Page 1

Phone Number Regex Page

Example 5

Simple phone number Phone Number Regex Example E.164 international format Phone Number Regex Example French mobile number Phone Number Regex Example US phone number Phone Number Regex Example Mobile numbers only Phone Number Regex Example

Guide 7

Why validate phone numbers with regex? Phone Number Regex Guide What is the E.164 phone number format? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Mobile numbers vs landline numbers Phone Number Regex Guide Formatting and user-friendly input with spaces, parentheses, dashes and other Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide

positive lookbehind

Concept 1

Positive lookbehind JavaScript Lookbehind Concept

Guide 1

Positive vs negative lookbehind JavaScript Lookbehind Guide

Private network

Example 1

Private IPv4 ranges IP Address Regex Example

Guide 1

Private vs public IP addresses IP Address Regex Guide

Profile

Page 1

Username Regex Page

Example 6

Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example

Guide 4

What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide

Punycode

Page 1

Domain Name Regex Page

Example 6

Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example

Guide 6

What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide

Quantifiers (* + ?)

Page 1

Regex Cheatsheet Page

Example 1

Minimum 8 characters Password Regex Example

Concept 5

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept

Guide 8

What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide Add quantifiers to repeat patterns Regex Tutorial Guide

Regex Engines

Page 1

JavaScript Regex vs PCRE Page

Concept 3

Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 8

Regex syntax differences between languages Regex Cheatsheet Guide What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

Repetition

Concept 1

Add repetition Regex Tutorial Concept

restrictive

Example 1

More restrictive email regex Email Regex Example

security

Page 1

Password Regex Page

Example 4

Minimum 8 characters Password Regex Example Letters and numbers Password Regex Example Strong password Password Regex Example Strong password (12+ chars) Password Regex Example

Guide 7

Why validate passwords with regex? Password Regex Guide Common password requirements Password Regex Guide Strong passwords vs complex passwords Password Regex Guide Can regex measure password strength? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide Modern password recommendations Password Regex Guide

seo

Page 1

Slug Regex Page

Example 5

Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 6

What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

simple pattern

Example 2

Simple email regex Email Regex Example Simple URL regex URL Regex Example

Guide 1

Should you use a strict or simple email regex? Email Regex Guide

slug

Page 1

Slug Regex Page

Example 5

Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 6

What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

Strict Validation

Example 1

More restrictive email regex Email Regex Example

Guide 1

Should you use a strict or simple email regex? Email Regex Guide

subdomain

Page 1

Domain Name Regex Page

Example 6

Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example

Guide 6

What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide

Sub-Domains

Example 1

Domain with subdomains Domain Name Regex Example

Guide 1

Subdomains and labels Domain Name Regex Guide

syntax

Page 1

Regex Cheatsheet Page

Concept 5

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept

Guide 7

What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide

Timestamps

Page 1

Date Regex Page

Example 5

DD/MM/YYYY Date Regex Example DD-MM-YYYY Date Regex Example ISO date Date Regex Example ISO datetime Date Regex Example Stricter DD/MM/YYYY Date Regex Example

Guide 7

Why validate dates with regex? Date Regex Guide Common date formats Date Regex Guide ISO 8601 date validation Date Regex Guide Can regex validate real calendar dates? Date Regex Guide Date format validation vs date parsing Date Regex Guide Common date validation mistakes Date Regex Guide When to use a date regex Date Regex Guide

TLD

Page 1

Domain Name Regex Page

Example 6

Simple domain name Domain Name Regex Example Domain with subdomains Domain Name Regex Example Strict domain labels Domain Name Regex Example Lowercase domain name Domain Name Regex Example Domain with optional trailing dot Domain Name Regex Example Punycode domain Domain Name Regex Example

Guide 6

What is a domain name? Domain Name Regex Guide Domain name vs URL Domain Name Regex Guide Subdomains and labels Domain Name Regex Guide Common domain validation mistakes Domain Name Regex Guide Can regex verify that a domain exists? Domain Name Regex Guide Internationalized domain names Domain Name Regex Guide

tokens

Page 1

Regex Cheatsheet Page

Concept 5

Anchors and boundaries Regex Cheatsheet Concept Character classes Regex Cheatsheet Concept Quantifiers Regex Cheatsheet Concept Groups and alternatives Regex Cheatsheet Concept Lookarounds Regex Cheatsheet Concept

Guide 7

What is a regex cheatsheet? Regex Cheatsheet Guide The most important regex tokens to know Regex Cheatsheet Guide Character classes explained Regex Cheatsheet Guide Understanding regex quantifiers Regex Cheatsheet Guide Groups, alternation and anchors Regex Cheatsheet Guide Regex syntax differences between languages Regex Cheatsheet Guide How to learn regex efficiently Regex Cheatsheet Guide

tutorial

Page 1

Regex Tutorial Page

Concept 4

Start with exact text Regex Tutorial Concept Use character classes Regex Tutorial Concept Add repetition Regex Tutorial Concept Test often Regex Tutorial Concept

Guide 7

How to learn regex step by step Regex Tutorial Guide Start with literal text Regex Tutorial Guide Use character classes for flexibility Regex Tutorial Guide Add quantifiers to repeat patterns Regex Tutorial Guide Use groups to organize your regex Regex Tutorial Guide Test regex patterns often Regex Tutorial Guide Common beginner mistakes Regex Tutorial Guide

Unicode

Page 2

Username Regex Page JavaScript Regex vs PCRE Page

Example 7

Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example Unicode slug Slug Regex Example

Concept 3

Common features JavaScript Regex vs PCRE Concept PCRE-specific strengths JavaScript Regex vs PCRE Concept JavaScript-specific behavior JavaScript Regex vs PCRE Concept

Guide 12

What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide Unicode slugs and international websites Slug Regex Guide What is PCRE? JavaScript Regex vs PCRE Guide Why do regex engines behave differently? JavaScript Regex vs PCRE Guide JavaScript regex vs PCRE JavaScript Regex vs PCRE Guide Lookbehind and modern regex features JavaScript Regex vs PCRE Guide Unicode support differences JavaScript Regex vs PCRE Guide Why does a regex work in a testing tool but not in my code? JavaScript Regex vs PCRE Guide Which regex engine should you learn? JavaScript Regex vs PCRE Guide

URL-safe

Page 1

Slug Regex Page

Example 5

Basic slug Slug Regex Example SEO-friendly slug Slug Regex Example Slug with underscores Slug Regex Example Fixed-length slug Slug Regex Example Unicode slug Slug Regex Example

Guide 6

What is a slug? Slug Regex Guide Why are slugs important for SEO? Slug Regex Guide Common slug rules Slug Regex Guide Slug validation vs slug generation Slug Regex Guide Unicode slugs and international websites Slug Regex Guide When to use a slug regex Slug Regex Guide

username

Page 1

Username Regex Page

Example 6

Letters and numbers Username Regex Example Letters, numbers and underscore Username Regex Example Username with length limit Username Regex Example Lowercase username Username Regex Example Username with hyphen Username Regex Example International username Username Regex Example

Guide 4

What is a username regex? Username Regex Guide Common username validation rules Username Regex Guide ASCII usernames vs Unicode usernames Username Regex Guide What regex cannot validate Username Regex Guide

UUID

Page 1

UUID Regex Page

Example 8

Simple IPv4 IP Address Regex Example Strict IPv4 IP Address Regex Example Private IPv4 ranges IP Address Regex Example IPv4 with CIDR IP Address Regex Example Standard UUID UUID Regex Example UUID v4 UUID Regex Example UUID v1 to v5 UUID Regex Example UUID without hyphens UUID Regex Example

Guide 6

IPv4 vs IPv6 IP Address Regex Guide What is a UUID? UUID Regex Guide Common UUID format UUID Regex Guide UUID versions UUID Regex Guide Can regex verify UUID uniqueness? UUID Regex Guide When to use a UUID regex UUID Regex Guide

validation

Example 2

Minimum 8 characters Password Regex Example Simple URL regex URL Regex Example

Guide 15

Why validate passwords with regex? Password Regex Guide Client-side and server-side validation Password Regex Guide Common password validation mistakes Password Regex Guide What makes email validation difficult? Email Regex Guide Common email validation rules Email Regex Guide Regex validation vs real email verification Email Regex Guide What is a valid URL? URL Regex Guide HTTP vs HTTPS URL validation URL Regex Guide Should a regex validate URLs completely? URL Regex Guide Common URL validation mistakes URL Regex Guide When to use URL regex validation URL Regex Guide Why validate phone numbers with regex? Phone Number Regex Guide International phone numbers are difficult to validate Phone Number Regex Guide Can regex verify a real phone number? Phone Number Regex Guide Best practices for phone number validation Phone Number Regex Guide

verification

Guide 1

Regex validation vs real email verification Email Regex Guide

Web - HTTP/HTTPS Links

Page 1

URL Regex Page

Example 2

Simple URL regex URL Regex Example HTTPS-only URL regex URL Regex Example

Guide 8

Why use a URL regex? URL Regex Guide What is a valid URL? URL Regex Guide HTTP vs HTTPS URL validation URL Regex Guide Should a regex validate URLs completely? URL Regex Guide Common URL validation mistakes URL Regex Guide When to use URL regex validation URL Regex Guide Domain name vs URL Domain Name Regex Guide Unicode slugs and international websites Slug Regex Guide