WQI.web​qualityindex

Security

HTTP Strict Transport Security

One header tells every future visitor 'always HTTPS, never HTTP, no exceptions'. Should ship everywhere; preload only after you're sure.

Authority
IETF
Version
RFC 6797
Jurisdiction
Global
Source
datatracker.ietf.org
Last reviewed
2026-04-28
Last verified
pending

What it is

Strict-Transport-Security — RFC 6797. A response header that pins the browser to HTTPS for max-age seconds, with optional includeSubDomains and preload tokens.

Why it matters

Without HSTS, a single MITM during a cleartext request is enough to strip TLS for a session. With HSTS, the browser refuses to downgrade. The base header is risk-free to deploy with a short max-age while you verify.

Who it applies to

Every HTTPS site — the base header is safe, preload is the irreversible commitment.

How WQI scores it

Web Quality Index considers this standard satisfied when the supporting factor passes.

# Factor Status
4 Security headers (HSTS, CSP, X-Frame-Options, Referrer-Policy, Permissions-Policy, X-Content-Type-Options) live

Related standards

See also
Security headers , TLS 1.2+

Standards that share factors with this one

Auto-computed from overlapping factor tickets in satisfiedBy, excluding standards already listed under "See also" above. Strong overlap suggests these standards rise and fall together when sites are scored.

Other references