Domain Name Validator
Validate domain names against RFC specifications instantly
Validation Results
How Does Domain Validation Work?
A domain is considered valid if it satisfies all the checks and measures listed below. Our domain name validator automatically checks the domain name against all relevant RFC specifications. These comprehensive checks include:
Valid Characters
A host-name can only contain English letters (a-z), digits (0-9), hyphen (-) and dot (.). Domain names can also contain underscore (_) and asterisk (*) for wildcard domains.
Hyphen Rules
Hyphens cannot be used at the beginning or end of a label. Consecutive hyphens as 3rd and 4th characters are not permitted except for Internationalized Domain Names (IDN). Two consecutive hyphens are usually not allowed, but this can vary by TLD.
Spaces and Special Characters
Spaces and most special characters (such as !, $, &, and others) are not permitted in domain names.
Top-Level Domain
A valid Top-Level Domain (TLD) must be present. This validator checks against a comprehensive list of 1,591 TLDs (Updated 22nd May 2024).
Domains Ending with Dot
Domain names with a dot (.) as the last character are considered valid and represent fully qualified domain names (FQDN).
Total Character Count
The total character count for a domain name, including TLDs and sub-domains, cannot exceed 253 characters.
Label Levels / Sub-domains
There cannot be more than 127 levels in a single domain name. For example, example.com has two levels.
Label Character Count
Each individual label (section between dots) must contain between 1 and 63 characters.
References: RFC 1034, RFC 1035, RFC 2181
Quick Bookmark
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Quick Tips
- Use lowercase letters for consistency
- Avoid hyphens at start or end
- Keep domain names short and memorable
- Check TLD availability and pricing