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Regex Pattern Library

A collection of commonly used regex patterns like email, URL, IP, and

A collection of commonly used regex patterns like email, URL, IP, and date, gathered by category. Click each pattern to see its explanation and examples, then run it right away in the tester.

Contact · Social

Contact · Social
Email
/[\w.+-]+@[\w-]+\.[\w.-]+/gi
A practical pattern that broadly catches email addresses. It allows dots, plus signs, and …
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Contact · Social
Hashtag
/(?:^|\s)(#[A-Za-z0-9_]+)/g
Matches hashtags that come after whitespace or the start of a sentence and captures the ta…
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Web · URL

Web · URL
URL
/https?:\/\/[^\s/$.?#].[^\s]*/gi
Matches web addresses that start with http or https. It captures the path, query, and frag…
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Web · URL
URL Slug
/^[a-z0-9]+(?:-[a-z0-9]+)*$/
Validates an entire URL slug made up only of lowercase letters, digits, and hyphens. Conse…
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Dev · Data

Dev · Data
IPv4 Address
/\b(?:(?:25[0-5]|2[0-4]\d|1?\d?\d)\.){3}(?:25[0-5]|2[0-4]\d|1?\d?\d)\b/g
Matches only valid IPv4 addresses where each octet is in the 0–255 range. Out-of-range val…
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Dev · Data
IPv6 Address
/(?:[A-F0-9]{1,4}:){7}[A-F0-9]{1,4}/gi
Matches a fully expanded IPv6 address made up of eight hexadecimal groups separated by col…
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Dev · Data
UUID v4
/\b[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-5][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}\b/gi
Matches standard UUIDs in the hyphen-separated 8-4-4-4-12 layout. It checks the version di…
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Dev · Data
HTML Tag
/<\/?([a-z][a-z0-9]*)\b[^>]*>/gi
Matches both opening and closing tags and captures the tag name in a capture group. It als…
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Date · Time

Date · Time
ISO Date (YYYY-MM-DD)
/\b\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])\b/g
Matches ISO 8601 dates in YYYY-MM-DD format. The month is limited to 01–12 and the day to …
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Date · Time
24-Hour Time
/\b([01]\d|2[0-3]):[0-5]\d(?::[0-5]\d)?\b/g
Matches 24-hour times from 00:00 to 23:59, with seconds (:SS) being optional. Each of the …
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Format · Code

Format · Code
HEX Color
/#(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{6})\b/g
Matches CSS HEX color codes with 3 or 6 hexadecimal digits after the #. Values with non-he…
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Security · Validation

Security · Validation
Username
/^[a-zA-Z0-9_]{3,16}$/
Validates a 3–16 character username made of letters, digits, and underscores. Spaces and s…
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Security · Validation
Strong Password
/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[^\w\s]).{8,}$/
A strong-password rule that uses lookaheads to check that at least one lowercase letter, u…
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Security · Validation
Credit Card
/\b(?:\d[ -]*?){13,16}\b/g
Matches 13–16 digit credit card number shapes that may be separated by spaces or hyphens. …
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