Regex Pattern Library

Collection of common regular expression patterns. Each pattern includes the regex, how to use it, matching and non-matching examples, and frequently asked questions.

Validation Patterns

Patterns for validating common input formats

Email Address Validation

^[\w.-]+@[\w.-]+\.\w{2,}$

URL Pattern

https?:\/\/[\w.-]+(:\d+)?(\/[\w./%-]*)?(\?[\w&=.-]*)?(#[\w-]*)?

Phone Number (US/International)

^\+?1?[-.\s]?$?\d{3}$?[-.\s]?\d{3}[-.\s]?\d{4}$

Date (YYYY-MM-DD)

^\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])$

Credit Card Number (Generic)

^(?:\d{4}[ -]?){3}\d{4}$

UUID v4

^[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-4[0-9A-Fa-f]{3}-[89ABab][0-9A-Fa-f]{3}-[0-9A-Fa-f]{12}$

Base64 Encoded String

^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$

Time (HH:MM 24-hour)

^(?:[01]\d|2[0-3]):[0-5]\d$

Network Patterns

Patterns for network-related data validation

IP Address (IPv4)

^(?:\d{1,3}\.){3}\d{1,3}$

Security Patterns

Patterns for password strength and security checks

Password Strength (8+ chars, mixed case, number, special)

^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[!@#$%^&*()_+\-={}\[\]|:;"'<>,.?\/~`]).{8,}$

Design Patterns

Patterns for design and color-related matching

Hex Color Code

^#?([0-9A-Fa-f]{3}|[0-9A-Fa-f]{6})$

Text Processing

Patterns for text processing and manipulation

URL Slug

^[a-z0-9]+(?:-[a-z0-9]+)*$

HTML Tag

<\/?[a-zA-Z][\w-]*(?:\s+[a-zA-Z][\w-]*(?:\s*=\s*(?:[^">]+|"[^"]*"|'[^']*'))?)*\s*\/?>

Whitespace Normalization

^\s+|\s+$|\s+(?=\s)

File Extension

\.(\w+)$