Regex Pattern Library — Common Patterns

Copy-ready regular expressions for email, URL, IP address, phone, credit card, UUID, date, and more. Click to copy, test against your input, and export as JSON. Free, no upload.

Pattern reference

Category	Pattern name	Best for	Flags
Validation	Email address	Sign-up forms, contact fields	none
Web & URL	URL (WHATWG spec)	Links, href attributes	gi
Web & URL	Domain name	Hostname validation	none
Numbers & IDs	UUID v4	Database IDs, tokens	none
Numbers & IDs	IPv4 address	IP allowlists, config	none
Numbers & IDs	IPv6 address	IP allowlists, config	none
Numbers & IDs	Credit card number	Form pre-validation (not secure)	none
Numbers & IDs	US phone number	North American numbers	gi
Security	Strong password	8+ chars, mixed case, digit, special	none
Dates & Times	ISO 8601 date	APIs, log timestamps	none
Dates & Times	US date (MM/DD/YYYY)	US-localised dates	none
Dates & Times	24-hour time	Timestamps, schedules	none
Text & Words	Slug / URL safe	URL slugs, identifiers	none
Text & Words	Hashtag	Social media parsing	gi
Text & Words	Hex color	CSS, design tokens	none

Why these patterns and not others

Most regex libraries either show a one-liner that passes most test cases but rejects valid inputs, or they show the RFC-correct 6,000-character monster that no one can maintain. This library takes a middle path: patterns that pass real-world inputs with known limitations clearly documented. Email uses the RFC 5321 practical subset, not the full RFC 5322 ABNF. URL uses the WHATWG spec, not the RFC. IPv4 handles dotted-quad with optional leading zeros. Credit card uses Luhn-aware length rules.

The copy button encodes the pattern for JavaScript regex literal syntax (`/pattern/flags`) where needed. For PCRE/PHP use the same pattern without delimiters. For Python, prepend `r""` or use the `re` module directly. For Go, use `regexp.MustCompile`. For .NET, the same literal works in most cases.

Pattern categories explained

Validation patterns enforce structure: they use `^` and `$` anchors to ensure the whole string matches. Search patterns leave anchors off so you can find matches inside longer text. The grid below labels each card with its primary use — validate or search — and the appropriate flags (`g` for global, `i` for case-insensitive).

Date patterns cover ISO 8601 (YYYY-MM-DD), US (MM/DD/YYYY), EU (DD/MM/YYYY) and ISO with time. Note that DD/MM/YYYY cannot be reliably distinguished from MM/DD/YYYY without context — both are valid formats for different locales, so choose based on your audience.

Next steps

Regex Tester— test a copied pattern live
Regex Explainer— understand what a pattern means

Frequently Asked Questions

How do I use these patterns?

Click any pattern card to copy it to your clipboard. Paste it into your code, a regex tester, or a search-and-replace tool. Most patterns are ready to use as-is; read the Notes column for anchors, delimiters, or language-specific caveats.

Are these patterns production-ready?

These are starting points, not battle-tested validators. Email (RFC 5322) and URL (RFC 3986) regexes are long by necessity — a short email pattern will reject valid addresses. Always validate against a representative sample before deploying, and prefer a purpose-built library for security-sensitive cases like credit card numbers.

Is my data sent to a server?

No. Every tool on jsonversal runs entirely in your browser using the Web Crypto API, File API, and Clipboard API. Nothing is ever uploaded — not even the JSON you paste in.

Do I need an account or API key?

No signup, no email, no API key. All tools are free to use with no signup required.

Can I use these tools offline?

Yes. Once the page loads, all tools work offline. There are no external API calls or CDN dependencies at runtime.

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Your data never leaves your device

All processing happens in your browser. No uploads, no tracking, no servers. Your API keys, configs, and private payloads stay private — 100% client-side.