Regex Library - Pattern Collection & Tester

About

Regex Library gives you instant access to 70+ battle-tested regex patterns — no more googling "regex for email" or writing patterns from scratch.

── PATTERN CATEGORIES ──

VALIDATION (30+ patterns):
• Email addresses (standard, strict, RFC 5322)
• Phone numbers (US, international, E.164)
• URLs (HTTP/HTTPS, any protocol)
• IP addresses (IPv4, IPv6, CIDR notation)
• Dates (ISO 8601, US format, European format)
• Times (12-hour, 24-hour)
• UUIDs (v4, any version)
• Hex colors (#RGB, #RRGGBB, #RRGGBBAA)
• Semantic versions (semver)
• Domain names, MAC addresses
• Credit cards (Visa, Mastercard, any with Luhn check)
• Passwords (weak, medium, strong)
• Usernames, ZIP codes, ISBN

EXTRACTION (15+ patterns):
• URLs from text
• Email addresses from text
• Phone numbers from text
• Hashtags and @mentions
• HTML tags and attributes
• Image sources (img src)
• Links (href attributes)
• Numbers (integers, decimals)
• Quoted strings
• JavaScript/HTML comments

FORMATTING (10+ patterns):
• camelCase to snake_case (and reverse)
• Whitespace normalization
• Line breaks (CRLF, LF, CR)
• Words and sentences
• CSV fields

PROGRAMMING (10+ patterns):
• JavaScript identifiers
• Python identifiers
• SQL keywords
• CSS selectors
• Import statements
• Function declarations

── LIVE TESTER ──
• Test any pattern against your text
• See matches highlighting in real-time
• View capture groups
• Try replace patterns
• Edit patterns on the fly
• Configurable flags (g, i, m)

── CODE SNIPPETS ──
• Copy pattern as JavaScript regex
• Copy as Python re pattern
• Copy as PHP preg_match
• Copy as Java Pattern

── FEATURES ──
• Search patterns by name or description
• Star favorites for quick access
• Right-click text to test it
• Dark and light themes
• Fully offline — patterns bundled locally

── PRIVACY ──
Regex Library runs entirely in your browser. Your patterns and test data stay on your machine. No accounts. No analytics. No external servers.

───────────────────────────────────────
Regex Library covers common patterns. DevKit covers everything else.
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