3 services carry this tag in their source record. Tags come from the provider, not from us — a tag is a claim about what the service does, not proof that it does it well.
The alt-svc response header of a URL: whether it is present, its value, and a one-line reading of what the value means (or the risk of its absence for security headers). One header, one answer, for audits and monitoring...
Change watch for response header alt svc: runs the check, compares it with the result from your previous call for the same url (kept 90 days) and returns the current answer, changed true/false, the fields that changed wi...
HTTP/3 and modern-transport support: checks the DNS HTTPS record (alpn, ech, ipv4hint), the Alt-Svc response header for h3, and reports whether HTTP/3 (QUIC), HTTP/2 and Encrypted Client Hello are advertised. Useful for...