What Are the Benefits of HSTS Preload?

The main benefits of HSTS Preload are stronger protection for HTTPS connections and eliminating HTTP-to-HTTPS redirects for old HTTP links. According to Semrush’s 2020 explanation, browsers that use a preload list change HTTP requests to HTTPS for listed sites, provided the site and its subdomains meet the preload requirements. This material supports the mechanism and benefits described above, but cannot establish the full application requirements in effect today.

Security benefit: switching to HTTPS even when an HTTP URL is used

HSTS stands for HTTP Strict Transport Security. It enforces the use of HTTPS, reducing the risk of an attacker tampering with requests or responses when users request pages over unencrypted HTTP. HSTS Preload uses a preload list to let browsers that adopt it identify which sites should use HTTPS.

According to the source, when a user attempts to open a listed site over HTTP, the browser checks the list and changes the request to HTTPS. The benefit is therefore not limited to situations where users click an HTTPS URL in the first place; even if they start with HTTP, the preload mechanism can switch them to a secure connection. This security benefit concerns connection and transport protection and should not be interpreted as resolving every security issue on a website.

Eliminating a redirect when old links still use HTTP

The source specifically notes that, for sites with many old backlinks that still use HTTP, the preload mechanism can eliminate unnecessary HTTP-to-HTTPS redirects. For example, an old article on another website might still link to a page using an HTTP URL. If the destination site is on the preload list used by the browser, the browser will use HTTPS based on that list rather than relying on an HTTP-to-HTTPS redirect for that visit.

• Security implications: Even when an old link uses HTTP, the preload mechanism can switch the connection to HTTPS.
• Performance implications: It eliminates the HTTP-to-HTTPS redirect described in the source, but the material provides no figures for time saved or improvements in loading speed.

Eligibility depends on the entire domain, not just a single page

This benefit does not automatically apply to every website. The source describes the preload list as containing sites whose entire domain and subdomains support HTTPS, and explicitly states that several requirements must be met to use this mechanism. A homepage being accessible over HTTPS is therefore not enough to establish that a site qualifies for preloading.

An assessment should separate two questions: whether the site has circumstances that could benefit, such as old HTTP links, and whether the entire domain and its subdomains meet the preload requirements. The former can demonstrate the value of using preloading, but cannot replace verification of eligibility. The supplied 2020 article does not list the complete requirements and cannot establish whether a particular site is currently eligible for inclusion.