headers6 min readBy Website Auditor ResearchUpdated 2026-01-14

Why Your Website Needs HSTS in 2026

One header, one config line, and downgrade attacks stop reaching your users. If your site doesn't ship HSTS in 2026, you're leaving free security on the table.

What HSTS does

Once a browser sees an HSTS header, it refuses to speak HTTP to that hostname for the duration of max-age. Every http:// link, redirect and typed URL is silently rewritten to https:// before it leaves the client.

Why now

Chrome and Safari both mark HTTP pages as Not Secure. Search engines demote HTTP pages. Modern browser APIs — Service Workers, WebAuthn, Push — refuse to work outside HTTPS. There is no benefit to leaving HSTS off in 2026.

How to ship it

Add Strict-Transport-Security: max-age=63072000; includeSubDomains; preload to your responses. Test with Website Auditor. Done.

Preloading

Submit at hstspreload.org. Every browser ships with your domain built in. Undoing preload takes months, so make sure every subdomain works over HTTPS first.

Frequently asked questions

Only if HTTPS breaks. It doesn't disable HTTP on the server, it just tells browsers not to use it.

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