Domain & Technical SEO Tools
Check domains, DNS, SSL, speed and crawlability.
14 tools · Real Data
Technical SEO is the plumbing behind every ranking page: whether search engines can crawl and index your site, whether it loads fast, whether it is served securely, and whether the domain itself is configured correctly. When this layer breaks — a bad redirect, an expired certificate, a robots rule blocking the wrong path — even perfect content can vanish from search. Most of these problems are invisible in a browser but easy to catch with the right check.
This category gives you those checks. Inspect DNS records and HTTP response headers, verify the SSL certificate chain, look up WHOIS and domain age, measure page speed and Core Web Vitals, test robots.txt rules, trace redirects, and find a site’s sitemap. Every tool queries the real domain live — real registries, the real certificate, the real server response — so you diagnose the actual configuration in production, not a cached copy, and fix issues before they cost you rankings.
After a migration, a domain change or a hosting move, run these checks in a fixed order: DNS Records Lookup to confirm records point where you expect, the Redirect Checker to verify old URLs reach their new home in a single hop, the Robots.txt Tester and Sitemap Finder to make sure nothing important is blocked, then the Technical Site Audit to crawl several pages for broken links and stray noindex tags. Certificate and speed checks have their own hubs, under website security and page speed.
Domain & Technical
14 toolsWHOIS Lookup
Retrieve real domain registration data: registrar, creation/expiry dates, name servers and status.
Open tool →DNS Records Lookup
Query live A, AAAA, MX, NS, TXT, CNAME, SOA and SRV records for any domain.
Open tool →SSL Certificate Checker
Inspect the live TLS certificate: issuer, validity dates, days remaining and SAN domains.
Open tool →HTTP Header Checker
View raw response headers, server software, caching, security headers and content type of any URL.
Open tool →Website Security Checker
Passive security scan of any website: HTTPS and TLS, HSTS, CSP and other security headers, exposed .env / .git / phpinfo fil…
Open tool →Redirect & HTTP Status Checker
Trace the full redirect chain (301/302/307) of a URL and verify the final status code.
Open tool →IP & Geolocation Lookup
Resolve a domain/IP and get real geolocation, ISP, ASN and hosting organization data.
Open tool →Robots.txt Tester
Fetch and parse a site’s robots.txt, test any URL against it for Googlebot and Bingbot, list rules per user-agent and locate…
Open tool →Sitemap Finder & Validator
Locate a domain’s XML sitemap(s), validate the format and count the URLs inside.
Open tool →Gzip / Brotli Compression Test
Check whether a URL serves compressed content and measure the bytes & percentage saved.
Open tool →Domain Age Checker
Find the registration date and exact age of any domain via live WHOIS data.
Open tool →Broken Link Checker
Crawl all links on a page and report dead links (4xx/5xx), redirects and their HTTP status codes.
Open tool →Mobile-Friendly Checker
Check viewport configuration, responsive meta tags and common mobile usability signals.
Open tool →Technical Site Audit (Crawler)
Crawl multiple pages of a site and aggregate technical SEO issues: broken links, missing titles, thin content, redirects and…
Open tool →Who uses these Domain & Technical tools
The audiences these tools fit best — each page collects the tools for that audience.
Guides for specific audiences
Pages that walk through one of these tools for a specific platform or profession.
- Squarespace Users: Redirect & HTTP Status Checker guide — Changed a Squarespace slug and worried old links now 404? Trace any old URL hop by hop and see the final status code it returns.
- Blogger Users: Robots.txt Tester guide — Test your Blogger custom robots.txt: see whether Googlebot can crawl each post, label page and search URL, and which line of the file decides it.
- News Publishers: Sitemap Finder & Validator guide — News sitemap not listing today's stories? Check for a missing news file, stale dates and missing tags before blaming Top Stories.
Frequently asked questions
What is technical SEO?
Technical SEO is the work that helps search engines crawl, render and index your site efficiently — covering site speed, security (HTTPS/SSL), crawlability (robots, redirects, sitemaps), DNS and correct domain configuration.
How do I check a site’s DNS or SSL for free?
Enter the domain into the DNS Lookup or SSL Checker tool. They query live DNS records and inspect the real certificate chain, returning results in seconds with no account.
Why does page speed matter for SEO?
Speed affects both rankings and conversions. Google uses Core Web Vitals as a ranking signal, and slow pages lose visitors before they load. The Page Speed tool measures load performance and flags what to improve.
Are these technical SEO tools free?
Yes. Every domain and technical tool here runs real, live lookups for free — no signup, no usage limits.
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