Regex for domain name

Note

Each label is 1–63 characters and cannot start or end with a hyphen. Internationalised names need converting to punycode first.

Matches in the example

• "example.com"
• "sub.example.co.uk"
• "my-site.dev"

Token by token

1. \b a word boundary
2. (?: a group, not capturing
3. [a-z0-9] one of: “a” to “z” or “0” to “9”
4. (?: a group, not capturing
5. [a-z0-9-]{0,61} one of: “a” to “z”, “0” to “9” or “-”, between 0 and 61 times, as many as possible
6. [a-z0-9] one of: “a” to “z” or “0” to “9”
7. )? end of group, whole group optionally
8. \. the character “.”
9. )+ end of group, whole group one or more times, as many as possible
10. [a-z]{2,63} one of: “a” to “z”, between 2 and 63 times, as many as possible
11. \b a word boundary

Other patterns

• Email address
• URL
• IPv4 address
• UUID
• Hex color
• Date (YYYY-MM-DD)
• Time (24-hour)
• US phone number
• Phone number (E.164)
• US ZIP code
• Credit card number
• URL slug
• Username
• Strong password
• HTML tag
• Semantic version
• MAC address
• JSON Web Token
• Hashtag
• @mention
• Number
• Leading and trailing whitespace
• Repeated word
• Blank lines
• Markdown link
• Quoted string
• Domain name
• File extension
• Base64
• Trailing comma