Domain Checker
Check domain availability and DNS records
How to use Domain Checker
Check domain name availability and DNS records for any domain. Supports all TLDs. Free online domain checker tool.
What is a domain checker used for?
Before registering a domain name for a new business, project, or personal website, you need to verify availability. Domain checkers also help diagnose DNS issues, verify ownership, and research competitors.
- New business naming: Check if your preferred domain is available before finalizing your business name — discovering that yourbrand.com is taken after printing business cards is a costly mistake.
- Brand protection: Check multiple TLDs (.com, .net, .org, .io, .co) to see which are available and which might be held by competitors or squatters.
- DNS troubleshooting: Verify DNS records (A, MX, NS, TXT) to diagnose email delivery issues, website downtime, or misconfigured subdomains.
- Email configuration: Check MX records to verify that a domain's email routing is correctly configured — essential when migrating to a new email provider.
- SPF and DKIM verification: TXT records contain SPF (Sender Policy Framework) and DKIM keys that authenticate outgoing email — query them to verify anti-spam configuration.
WHOIS lookup: A domain checker can also retrieve WHOIS data — the registrant information, registration date, expiry date, and registrar. Many domains use privacy protection services that mask registrant details, but expiry dates remain visible — useful for monitoring domains you want to acquire when they lapse.
Frequently Asked Questions
What is the difference between a domain name and a URL?
A domain name identifies a website (flashutils.com). A URL (Uniform Resource Locator) is the complete address including protocol, domain, path, and query string: https://flashutils.com/en/password-generator/?ref=home. The domain is one component of the URL. A domain is registered; a URL is constructed.
What is a TLD and which one should I choose?
.com is the most recognized and trusted TLD worldwide — always prefer it if available. .org is associated with non-profits and open-source projects. .net is the traditional alternative to .com. Country TLDs (.es, .co.uk, .de) signal geographic focus and may rank better locally. New TLDs (.io, .app, .dev) are popular in tech — .io in particular is widely used by SaaS products despite being the Indian Ocean territory code.
What is DNS propagation?
When you change DNS records (like updating nameservers after transferring a domain, or changing the A record to a new hosting IP), the change must propagate across DNS servers worldwide. This can take anywhere from a few minutes to 48 hours. During propagation, some users see the old site and others see the new one. TTL (Time To Live) values control how long DNS resolvers cache records.
What is the difference between A, CNAME, MX, and TXT records?
A record: maps a domain to an IPv4 address. AAAA record: maps to IPv6. CNAME: aliases one domain to another (www.example.com → example.com). MX: specifies mail servers for the domain — required for email to work. TXT: stores text data — used for SPF, DKIM, domain ownership verification, and Google Search Console.
What happens when a domain expires?
After expiry, there is typically a grace period (30-45 days) during which the owner can renew. Then a redemption period (30 days) where renewal costs significantly more. Finally, the domain is released for public registration. Premium expired domains with existing backlinks are valuable and often bought immediately by domain investors.
Domain checker vs WHOIS vs DNS lookup vs SSL checker
A domain checker verifies availability and basic domain information. A WHOIS lookup retrieves registrant details, registration dates, and expiry. A DNS lookup (dig, nslookup) queries specific DNS records in real time. An SSL/TLS checker (SSL Labs) verifies certificate validity, expiry, and configuration. A website monitor checks uptime and response time continuously. For comprehensive domain health, use all of these together — they answer different questions about the same domain.