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DomainApp is a free suite of 19 domain tools. Check WHOIS records, look up DNS, verify SSL certificates, inspect HTTP headers, audit SEO, check DMARC/SPF/DKIM, browse certificate transparency logs, find expired domains, and discover available domain names.
See domain registration details including registrar, creation date, expiry, domain age, and nameservers.
View A, AAAA, MX, NS, TXT, CNAME, and SOA records for any domain.
Verify SSL/TLS certificates — issuer, validity dates, days remaining, and subject alternative names.
Inspect server response headers including security headers, caching, and redirects.
Follow the full redirect chain from HTTP to final destination. See each hop with status codes.
Check mail server records and verify they are reachable on SMTP ports.
Check if a domain's IP is listed on major spam blacklists (Spamhaus, Spamcop, Barracuda, SORBS, and more).
Detect the CMS, JavaScript framework, CSS framework, CDN, analytics, and hosting platform used by any website.
Check for robots.txt, sitemap.xml, ads.txt, security.txt, and other common files.
Check if a username is available on GitHub, Twitter/X, Instagram, TikTok, Reddit, YouTube, and more.
Measure DNS resolution, TCP connect, and total page load time with color-coded results.
See exactly how old a domain is — creation date, age in years/months, and total days since registration.
Identify who hosts a domain — IP address, organization, ASN, reverse DNS, and detected provider name.
Discover available domain names with pronounceable, memorable patterns. Filter by .com, .net, .org and more.
Generate domain ideas from keywords with common prefixes and suffixes across multiple TLDs.
Verify your email authentication setup. Check SPF policy (-all vs ~all), DMARC policy (reject, quarantine, none), DKIM selector presence, and aggregate report addresses.
Browse all SSL/TLS certificates ever issued for a domain via crt.sh. Discover subdomains, detect misissued certificates, and track certificate history.
Audit on-page SEO in one click. Checks HTTPS, title length, meta description, H1 tag, canonical URL, viewport, Open Graph tags, Schema.org markup, image alt text, and page size — with a score out of 100.
Check if a domain has DNSSEC enabled. Verifies DNSKEY records, DS records at the parent zone, RRSIG signatures, and the AD (Authenticated Data) flag confirming resolver validation.