SSL, DNS, domain, and website tools - free, instant, no signup required.
Check and monitor SSL/TLS certificates.
Instantly check a domain's SSL certificate status, expiry date, issuer, and full...
Check exactly when a domain's SSL certificate expires and how many days remain.
Check which TLS version and signature algorithm a website's server supports.
Look up and inspect DNS records.
Instantly look up A, AAAA, MX, TXT, NS, CNAME, SOA, and CAA records for any doma...
Look up a domain's A records - the IPv4 addresses it points to.
Look up a domain's AAAA records - the IPv6 addresses it points to.
Look up a domain's MX records to see which mail servers handle its email.
Look up a domain's TXT records - often used for SPF, domain verification, and mo...
Look up a domain's NS records to see which nameservers manage its DNS.
Look up a domain or subdomain's CNAME record.
Look up a domain's SOA (Start of Authority) record.
Domain registration, expiry, and ownership tools.
Look up a domain's registration details - registrar, registration date, and expi...
Check exactly when a domain name expires.
Check how old a domain name is.
Find out which registrar a domain is registered with.
Find out which nameservers a domain uses.
Look up a domain's registration data using the modern RDAP protocol, with automa...
Look up information about a domain's TLD (top-level domain) - its registry opera...
Check whether a domain name is registered or available, using public WHOIS/RDAP...
Look up the hostname associated with an IP address.
Find the domain name associated with an IP address, where publicly available.
Check the status and health of any website.
Instantly check any website's uptime status, HTTP status code, and response time...
Look up a website's server IP address, IPv4/IPv6, and reverse DNS.
Check the HTTP status code any website returns.
View every HTTP response header a website sends.
Check whether a website redirects and where it ends up.
Check how fast a website responds to a request.
Check whether a website has a robots.txt file and view its contents.
Check whether a website has an XML sitemap.
Scan for common website security issues.
Scan a website's HTTP response for recommended security headers and get a score...
Check whether a website properly redirects visitors to HTTPS.
Check whether a website sends the Strict-Transport-Security (HSTS) header.
Check whether a website sends a Content-Security-Policy header.
Check whether a website sends an X-Frame-Options header to prevent clickjacking.
Check whether a website sends an X-Content-Type-Options header to prevent MIME-s...
Check whether a website sends a Referrer-Policy header.
Check whether a website sends a Permissions-Policy header.
Check a website's CORS (Cross-Origin Resource Sharing) headers.
Check whether a website's security headers protect against mixed content.
Email deliverability and configuration tools.
Check whether a domain has a valid SPF record configured.
Check whether a domain has a DKIM record configured under common selectors.
Check whether a domain has a DMARC policy configured.
Check a domain's mail server (MX) records and their priority.
Check whether a domain's mail server is reachable on standard SMTP ports (25, 46...
Look up a domain's mail server hostnames, IP addresses, and reverse DNS.
A combined overview of a domain's MX, SPF, DKIM, and DMARC configuration with an...
Measure and monitor website performance.
Check whether a website serves compressed (GZIP/Brotli) content.
Check whether a website serves Brotli-compressed content.
Detect which HTTP protocol version a website serves (HTTP/1.1, HTTP/2, or HTTP/3...
Analyze a website's caching headers - Cache-Control, Expires, ETag, Last-Modifie...
Check whether a website supports persistent (Keep-Alive) connections.
Check which content encoding (gzip, br, deflate, or identity) a website uses.
Check the HTML response size of a website's homepage.
Detect whether a website uses a common CDN provider.
A combined overview of a website's compression configuration - GZIP, Brotli, and...
A combined performance overview - response time, compression, HTTP version, keep...
Lightweight on-page SEO analysis for any URL.
Check a page's title tag for presence and optimal length.
Check a page's meta description for presence and optimal length.
Check whether a page has a canonical URL tag.
Check a site's robots.txt file and its sitemap reference, from an SEO perspectiv...
Check a site's XML sitemap, from an SEO perspective.
Check a page's Open Graph tags for social sharing previews.
Check a page's Twitter Card tags for social sharing previews.
Check a page's H1-H6 heading structure.
Check a page for images missing alt text.
Check a page for JSON-LD structured data (Schema.org markup).
Check whether a page is indexable - noindex directives and crawlability signals.
A combined on-page SEO overview - title, meta description, canonical, headings,...