Regex Pattern Library

Generators

Curated library of common regex patterns for email, URL, phone, and more.

Email address

/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/i

URL

/https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)/i

Phone (US)

/^(\+1)?[-\s.]?\(?[0-9]{3}\)?[-\s.]?[0-9]{3}[-\s.]?[0-9]{4}$/

IPv4 Address

/^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/

Date (YYYY-MM-DD)

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

Credit Card

/^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|3[47][0-9]{13}|3(?:0[0-5]|[68][0-9])[0-9]{11}|6(?:011|5[0-9]{2})[0-9]{12})$/

Zip Code (US)

/^[0-9]{5}(?:-[0-9]{4})?$/

Hex Color

/^#?([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/

Strong Password

/^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[!@#$%^&*])(?=.{8,})/

HTML Tag

/<([a-z]+)([^<]+)*(?:>(.*)<\/\1>|\s+\/>)/gi

Slug

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

Username (3-16 chars)

/^[a-zA-Z0-9_-]{3,16}$/

#regex library#regex patterns#email regex#url regex

About Regex Pattern Library

Curated library of common regex patterns for email, URL, phone, and more. Regex Pattern Library runs entirely in your browser — no installation, no uploads, and no data ever leaves your device.

Common use cases: find a proven regex for email or url validation; copy tested patterns directly into form validation code; learn regex syntax from annotated real-world examples. Whether you are debugging, prototyping, or building production code, having a fast and private tool for this task saves time compared to writing one-off scripts or using an online tool that logs your data.

Like every tool in Catalyst, this one is free forever, requires no login, and is safe to use with confidential data. All processing happens client-side via native browser APIs.

How to use Regex Pattern Library

1
Open the tool
Open Regex Pattern Library directly — no signup or installation required. The interactive interface loads instantly.
2
Paste or enter your input
Drop your data into the input area. The tool validates and processes your input live as you type or paste.
3
Review the result
The output updates instantly. If the tool has configuration options, adjust them and watch the result update.
4
Copy or download
Use the copy button to send the result to your clipboard. Nothing is saved between page loads, so closing the tab discards everything.

Frequently asked questions

Is any data sent to a server?

No. The tool runs entirely in your browser using native JavaScript and Web APIs. Nothing you paste or upload is transmitted, logged, or stored. You can verify this by disconnecting your network and seeing the tool continue to work.

Is this tool free to use?

Yes. It's completely free with no login, signup, API key, or usage limits. Catalyst is funded by ads and will remain free forever.

Does it work offline?

Once the page has loaded, yes. All processing happens locally in your browser, so you can use the tool on airplanes, trains, or in air-gapped environments.