In a recent Google SEO Office Hours session, a query arose regarding the potential ranking influence of a security header.
This question is more plausible than it may seem initially. Security headers such as the HSTS header play a vital role in ensuring a secure HTTPS connection, and given that HTTPS serves as a lightweight Google ranking signal, their relevance becomes apparent.

The HSTS Security Header

A header, a server’s response to a browser or crawler, provides critical information about a webpage. Common examples include the 404 Error Response or the 301 response header.
HTTP headers furnish additional metadata regarding the webpage a browser or crawler requests.
Security headers form a distinct category aimed at bolstering various security measures safeguarding sites against diverse malicious attacks to ensure user safety.
The HSTS (HTTP Strict Transport Security) security header is a response that instructs the browser to access the webpage via HTTPS, never through HTTP exclusively, and to request HTTPS consistently in the future.
Employing this header surpasses solely relying on a 301 redirect. When a browser initially accesses a site through HTTP and gets redirected to HTTPS, subsequent requests may revert to asking for an HTTP page, necessitating repeated redirection by the server.
Crucially, a site using solely a 301 redirect remains susceptible to potential man-in-the-middle attacks.
Implementing an HSTS header effectively prevents such occurrences by compelling the browser to seek only HTTPS pages, thereby significantly enhancing the overall site security regarding HTTPS protection.

Inquired of John Mueller: “Does implementing security headers like HSTS impact rankings?”

John Mueller responded: “No, the HSTS header doesn’t impact search rankings.
This header primarily instructs users to access the HTTPS version directly and is often coupled with redirects to the HTTPS versions.
Google employs canonicalization to determine the most suitable page version for crawling and indexing, which doesn’t hinge on headers like those used for HSTS.
However, employing these headers remains beneficial for enhancing user experience.”

HSTS: An Essential Security Measure

While HSTS communicates directly with browsers and, as per John Mueller, Googlebot doesn’t hinge its operations on headers, prioritizing robust security practices is crucial for every website, irrespective of their potential impact on rankings.
Chrome maintains an HSTS preload list, integrated into all browsers, ensuring automatic adoption of HTTPS. This list is hardcoded into the browser.
Guidelines for implementation are available on the HSTS Preload website for those interested in the process.

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