About

Last updated 2026-07-26

What this is

WebsiteInfo takes a single domain and checks certificate expiry, email spoofing protection (SPF, DMARC, DKIM), DNS configuration, HTTP security headers and public files — all in one pass.

It exists because most diagnostic tools stop at "SPF: FAIL". This one also explains what the item means, why it matters, and exactly how to fix it.

How the checks work

Public DNS records are queried, a TLS connection is opened to read the certificate, and the first page is fetched over HTTPS to inspect its response headers. All of it is information anyone can look up, and none of it burdens the site being checked.

Repeated checks of the same domain reuse the result for five minutes, so no unnecessary requests are sent.

Who runs it

Built and operated by one person on a Linux server at home. Questions and corrections are welcome at [email protected].