How does HTTPS affect indexing, security, and website speed?

HTTPS directly protects the privacy and integrity of data in transit and verifies the server’s identity; indexing and speed cannot be assessed simply by whether a certificate is installed. Historical sources indicate that Google gave HTTPS indexing priority under certain conditions, but this did not guarantee inclusion in the index or higher rankings. Performance also depends on encryption overhead, transfer protocols, and caching configurations, so switching to HTTPS cannot be described as universally faster or slower.

Security: protecting data in transit does not address every website risk

A 2016 article by awoo explains that HTTP transmits data in plain text, creating risks of eavesdropping, tampering, and hijacking; HTTPS uses SSL/TLS to provide encryption, authentication, and integrity protection. These protections apply to communications and should not be taken to mean that all website security issues have been resolved.

Migration also requires checking the resources referenced on each page. For example, even if a page’s URL uses HTTPS, its images, scripts, or stylesheets may still use HTTP. Checking the address bar alone is not enough to declare the migration complete.

Indexing: historical priority came with explicit conditions

In 2016, awoo relayed Google’s explanation at the time: when HTTP and HTTPS URLs on the same domain had similar content, Google would try to prioritize indexing the HTTPS version and give it a slight ranking benefit. The article listed the following conditions:

• There is no insecure content, and a valid TLS certificate is in place.
• Crawling is not blocked by robots.txt, and noindex is not set.
• The URL does not redirect to HTTP, and its canonical does not point to HTTP.
• No external URLs link to the HTTP version; the sitemap lists HTTPS or does not list the HTTP version.

This is a historical explanation, not a complete list of current rules. The same article also noted that both versions could still be indexed and recommended using 301 redirects from HTTP pages to HTTPS. Indexing priority should not be interpreted as meaning that old URLs will necessarily disappear automatically.

Migration checks: crawler reports help identify omissions, but have coverage limits

Screaming Frog’s 2015 documentation stated that its insecure content report could identify HTTP links, images, JS, CSS, and other items on HTTPS pages; its 2020 documentation added that the older report also checked elements such as canonical and hreflang.

However, the 2015 documentation explicitly limited the report’s coverage to items crawled by the tool, rather than everything rendered by a browser. A report that lists no issues therefore cannot be treated as proof that all resources are secure.

Speed: encryption overhead and transfer improvements need separate comparisons

awoo’s 2016 article noted that encrypted communications increase CPU usage and server response time, with the impact also depending on the encryption mode and keys. The same article suggested that CDN caching and serving content from nearby nodes could reduce the host server’s bandwidth burden, and introduced HTTP/2’s compression and multiplexing mechanisms.

These effects operate at different levels. If a CDN or HTTP/2 is introduced during migration, any change in speed cannot be attributed entirely to HTTPS. The supplied material provides no before-and-after tests under the same conditions, so it cannot establish how much HTTPS speeds up or slows down a website.