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web validator

Domain Validator

Validate domain names with proper labels and TLDs—client-side only.

Results

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Status
Processing...
Details
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How to use this validator

  1. Paste the domain.
  2. Run validate to check labels and TLD.
  3. If invalid, remove underscores/invalid chars and ensure a TLD is present, then re-run.

Rules & checks

Requires a valid TLD and label structure.

Blocks underscores and invalid characters.

Does not resolve DNS—format-only.

Inputs explained

  • Domain

    Enter a full domain like example.com or sub.example.co.uk. Lowercase is recommended.

When to use it

  • Validate domains in signup or lead forms
  • Check domains before configuring SSL or DNS records
  • Verify partner domains in integrations

Common errors

  • Missing TLD or trailing dot
  • Underscores or invalid characters in labels
  • Leading/trailing hyphens in a label

Limitations

  • Format-only; does not resolve DNS, check availability, WHOIS, or ownership.
  • IDN/punycode is not converted here; use punycode-aware validation if you need full internationalized domain support.
  • Does not confirm live MX/HTTPS/CAA/NS records—pair with MX/SPF/DKIM/DMARC/CAA validators.
  • No URL parsing here—supply bare domains; use the URL validator for full URLs.

Tips

  • Require https URLs separately if you need protocol checks
  • Keep domains lowercase to avoid confusion
  • Trim whitespace before validation

Examples

Valid domain

  • example.com -> Valid

Valid subdomain

  • cdn.example.co.uk -> Valid

Invalid (no TLD)

  • example_local -> Invalid (missing TLD)

Invalid chars

  • exa_mple.com -> Invalid (underscore not allowed)

Deep dive

This domain validator checks label/TLD format client-side, blocking underscores, leading/trailing hyphens, and missing TLDs without doing DNS lookups.

Use it to clean domains in forms and configs before hitting your backend, then layer DNS checks (MX/SPF/DKIM/DMARC) if needed.

FAQs

Do you check DNS or availability?
No. This validates format only; it doesn’t resolve DNS or WHOIS.
Can subdomains be used?
Yes, as long as they include a valid TLD and conform to label rules.
Is anything stored?
No. Validation runs locally and clears on refresh.
Do you handle IDN domains?
This is ASCII-focused. Convert IDNs to punycode first if needed.
Why did my domain fail?
Common reasons: missing TLD, underscores, leading/trailing hyphens, or invalid characters.

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