Fibonacci ToolBox

Meta tags & link preview

See a page the way search engines and chat apps do: title, description, Open Graph, Twitter card, canonical and headings.

Meta tags & link preview options
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DNS lookup

Query A, AAAA, MX, TXT, NS, SOA, CAA and more through public resolvers, with TTLs.

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Email DNS checker

Check a domain's MX, SPF, DMARC, DKIM, MTA-STS and BIMI setup, with a pass/fail verdict per record.

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SSL certificate checker

Inspect a server's TLS certificate: issuer, SANs, expiry, key, protocol and cipher.

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HTTP headers & redirects

Follow a URL's redirect chain and inspect status codes, response headers and security headers.

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