DomainDNSCheck.com is a free, independent website for checking and understanding how a domain is set up. It brings together DNS lookups, DNSSEC validation, registration data from RDAP, SSL/TLS and HTTP checks, email-security tools (SPF, DKIM, DMARC, MTA-STS, TLS-RPT and BIMI), Certificate Transparency, a domain report, a domain security report and optional monitoring.
Purpose
The infrastructure behind a domain name is spread across registries, registrars, name servers, certificate authorities and mail systems. Each layer has its own standards and terminology, and a problem in one layer often shows up as a confusing symptom in another. DomainDNSCheck exists to make that infrastructure understandable for domain owners, developers, hosting providers and IT teams anywhere in the world.
We have three goals:
- Explain, not just display. Every tool shows what a result means, why it matters and what you might do next.
- Be honest and transparent. Tools report what they actually observed, with clear limits on what a check can and cannot tell you.
- Support learning. The guides explain the standards behind each check in plain language.
Principles
No dark patterns. There are no countdown timers, fake scarcity messages or prompts designed to push you toward a purchase. DomainDNSCheck does not sell domains or hosting.
No mass-indexed pages about other people's domains. Results are generated when you request them. We do not publish result pages for search engines or build a public directory of other people's domains.
Passive checks only. The tools read public DNS, registration, certificate and HTTP information. DomainDNSCheck does not scan ports, test for vulnerabilities, crawl websites or attempt logins.
How it works
DomainDNSCheck queries public, standards-based sources and shows you what they return.
- DNS records are resolved through public DNS-over-HTTPS resolvers.
- Registration data comes from RDAP (Registration Data Access Protocol) servers, found through the IANA bootstrap registry.
- Web checks, including SSL/TLS certificates and HTTP responses, use direct connections from our servers to the host you specify, with strict safeguards against private and internal addresses.
- Domain structure, such as which part of a name is the registrable domain, is determined with the Public Suffix List.
Results may be cached briefly to reduce load on upstream services, so a very recent change can take a few minutes to appear. The methodology page explains each data source, the scoring rules and the known limits in detail.
Privacy
You do not need an account to use the tools. We do not keep a permanent history of what visitors look up, and the domains you check are never sent to our analytics. Analytics cookies are used only as the privacy policy describes, with consent where the law requires it. An optional free account is used only for domain monitoring. The privacy policy describes exactly what we process and for how long.
Accuracy and limits
When a check cannot determine something, the result says so: unknown is reported as unknown, never filled in with an assumption. Domain availability is never overstated — a lookup can suggest that a name appears unregistered, but only a registrar or registry can confirm it. See the disclaimer for how to use the results.
Contact
If you have feedback, notice an error or want to report a problem with a tool, please use the contact page.