Free Domain and Website Lookup Tools

Domain lookup tools show the public facts behind a website: its DNS records, its SSL certificate and its registration details. The free tools here check A, AAAA, MX, TXT, CNAME and NS records, certificate issuer, expiry and covered domains, and registrar, registration and expiry dates through RDAP, which helps you diagnose email, trust and ownership issues.

A 2002 Stanford Persuasive Technology Lab study of 2,684 people judging live websites found that design look was the most frequently mentioned credibility factor, appearing in 46.1% of comments, which is a reminder that visitors judge trust quickly and a browser warning or broken email can undo it.

I built these lookups because the same few questions come up in nearly every technical audit. Where does this domain point? Is the certificate about to expire? Who registered it and when does it lapse? The answers are public, but they are scattered across command line tools and registrar dashboards. Here they are in one place, in plain language.

This page covers what each tool shows, how to read it, what to fix and where the limits are. The wider toolkit is listed on the free SEO tools hub.

DNS Lookup

DNS is the system that turns a domain name into the addresses and services behind it. This tool looks up A, AAAA, MX, TXT, CNAME and NS records for a domain. It runs in your browser: your browser asks a public DNS over HTTPS service for the records and shows you what it receives.

What each record tells you

• A and AAAA point the domain to an IPv4 or IPv6 address. If your site moved hosts and the A record still shows the old address, visitors can land on the old server.
• CNAME makes one name an alias of another. It is common for the www version of a site, and for pointing a subdomain to a service.
• MX records say which servers receive email for the domain. Missing or wrong MX records are the usual reason a new domain cannot receive mail.
• TXT records hold text used for verification and email authentication. You will often see ownership tokens and sender policy entries here.
• NS records show which nameservers are authoritative for the domain. They tell you where DNS is actually managed, which is often not where you think.

What to fix

Check that both the bare domain and the www version resolve, and that one redirects to the other. Check that old hosting addresses are gone after a migration. If email is failing, compare MX and TXT against what your mail provider tells you to publish. A change you make at your DNS provider can take time to spread, so a lookup straight after an edit may still show the old value.

SSL Certificate Checker

An SSL (TLS) certificate lets browsers connect to your site over HTTPS. This tool shows who issued a site’s certificate, when it expires and which domains it covers. Our server connects to the site and reads the certificate it presents.

Reading the result

• Issuer. Confirms which certificate authority issued it. An unexpected issuer can mean a hosting default or a forgotten certificate.
• Expiry date. The key field. An expired certificate causes browser warnings that stop most visitors immediately.
• Covered domains. If your site works on example.com but the certificate does not list www.example.com, the www version may show a warning.

What to fix

Set a reminder well before expiry, or confirm that automatic renewal is working. Make sure every hostname you serve is covered, including subdomains. Then confirm that HTTP redirects to HTTPS. Google’s own guidance on enabling HTTPS explains why it matters for protecting pages from interception and tampering and notes it is a positive search signal.

The checker shows the certificate. It does not audit your whole HTTPS setup, so mixed content, weak server settings and redirect chains need separate checks. The technical SEO tools cover status codes and redirects.

Domain WHOIS and Age Lookup

This tool shows registration and expiry dates and the registrar, using the public RDAP system, which is the modern replacement for classic WHOIS. It is useful for checking when a domain was registered, when it expires and who manages it.

Reading the result

• Registration date. The age of a domain is a fact, but age alone is not a ranking shortcut. I use it for due diligence, for example when buying a domain or checking a competitor.
• Expiry date. A lapsed domain takes your site and email offline. Put the date in a calendar.
• Registrar. Tells you where to log in to renew or change nameservers.

Honest limits

Many registries redact personal contact details, so do not expect to see an owner’s name or email. Coverage also differs by extension. Some country code domains do not publish RDAP data in the same way, so you may see limited or no results. A missing result is a limitation of the registry, not necessarily a problem with the domain.

How these tools work and their limits

Unlike the browser-only tools elsewhere in the toolkit, all three lookups here are server-checked. You enter a domain, our server makes the query or connection, and the result is shown to you. Domain names are public information, so you should not enter anything private. Do not paste credentials or internal hostnames that you want to keep secret.

A few points to keep in mind:

• Results reflect what the server sees at that moment. DNS caching means another resolver may briefly show something different.
• Some servers block automated connections or time out. A failed check does not always mean the site is down.
• The tools read public data. They cannot show your registrar login, private zone records or internal DNS.

These tools describe facts. They do not score your domain, and I have deliberately not added a made-up authority number, because it would not reflect anything real.

A workflow for a domain health check

1. Start with WHOIS and Age. Confirm the registrar and the expiry date, and note who holds the login.
2. Run the DNS Lookup. Check NS to find where DNS lives, then A, AAAA and CNAME for the website, and MX and TXT for email.
3. Run the SSL Certificate Checker. Check the expiry and that both bare and www hostnames are covered.
4. Fix in order of damage. Expired or soon to expire items first, then email records, then tidy-ups.
5. Recheck after changes. Allow time for DNS to spread, then run each lookup again.

Imagine you are migrating a site to new hosting. Before the move, you note the current A record and the certificate expiry. After the move, you compare. If the A record is new but email now fails, the lookup of MX records often shows that records were lost during the nameserver change. This is an illustrative example, not a client result.

For migrations, also check the on-page elements that tend to break, using the on-page SEO tools.

When a tool is not enough

Lookups tell you what exists. They do not tell you whether it is right for your business, or why something that looks right still fails. A professional audit is worth considering if email deliverability is poor with correct-looking records, if you are moving a large site and need to protect organic traffic, if you have many subdomains or several certificates to manage, or if a security warning keeps returning.

In those cases the answer is usually in how DNS, hosting, redirects and the site itself fit together. I can review the whole chain and tell you what to change first.

Questions people ask about domain lookup tools

If something in your lookups looks wrong and you are not sure what to change, my technical SEO services cover DNS, HTTPS and migrations, and you can request a free audit to have it reviewed.