Domain Name Validator
Validate domain names against RFC 1035 rules: length, characters, labels, and TLD.
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FAQ
- What are the rules for a valid domain name?
- Per RFC 1035: total domain length must be ≤253 characters, each label (part between dots) must be 1–63 characters, labels may contain letters (a-z), digits (0-9), and hyphens, labels must not start or end with a hyphen, and the TLD must be at least 2 characters and all alphabetic.
- What is a domain label?
- A label is a segment of a domain name separated by dots. In "www.example.com", the labels are "www", "example", and "com". Each label has its own length and character restrictions.
- Does this tool check if a domain is actually registered?
- No, this tool validates the format and syntax of domain names only. It does not perform DNS lookups or check WHOIS data to verify if a domain is registered or active.
Enter a domain name to validate it against RFC 1035 and related standards. Checks total length (max 253 chars), individual label length (max 63 chars), allowed characters (letters, digits, hyphens), hyphen position rules, and TLD validity. Shows a detailed breakdown of each validation rule.