John Mueller, webmaster trends analyst at Google, recently posted thirteen FAQs on migrating from HTTP to HTTPS. Mueller followed up on the post, providing greater insight, by answering questions asked by readers in the comments.
Rather than cover them in Q&A form, we will provide a summary of all the information revealed in John Mueller's post:
- Search Console — When migrating from HTTP to HTTPS you only need to add the HTTPS website to it. The change-of-address setting doesn't apply for HTTP to HTTPS transfers.
- A/B Testing — If you are currently using HTTP, but want to carry out A/B tests with HTTPS then you should use 302 redirects (these are not cached) and rel-canonical back to the HTTP version of the page. You should not block HTTPS via Robots.txt. A useful guide was posted back in 2009 about A/B testing. The rel=canonical doesn't guarantee that the HTTP URL will be indexed, but it is a strong signal.
- Migration to HTTPS — Once you have made the decision to migrate, then you should follow Google's site-move guidelines. You should add 301 directs to the HTTPS version, ensure the rel=canonical tag is on every page pointing to the new version. You should also submit sitemaps for BOTH HTTP and HTTPS URLs as this helps Google pick up the changes. In the long term, only the HTTPS sitemap is required.
- Robots.txt file — The HTTPS website will use the HTTPS version of the robots.txt file. You should ensure that it is reachable. Also, you should make sure that your HTTP URLS are not blocked by your HTTP version of the robots.txt file.
- A mix of HTTP and HTTPS — Your website can mix HTTP and HTTPS pages. For instance, if you want just your administration or checkout pages to be served with encryption that is fine. Equally, if you are migrating a whole website to HTTPS, it is ok to do so in sections.
- Ranking Drops — Fluctuations in rankings may happen with any significant website change. While Google can't make any guarantees, their systems are "usually good with HTTP -> HTTPS moves."
- SSL Certificate — Any modern certificate accepted by modern browsers is sufficient.
- PageRank Loss — For 301 and 302 redirects from HTTP to HTTPS, no PageRank is lost.
- Search Keywords — After moving to HTTPS, you can still see search keywords from within the Search Console. Nothing changes.
- Testing HTTPS indexing — If you verify both HTTP and HTTPS websites separately in the search console you can use the Index Status report, or the sitemap index counts to check indexing rates.
- Time to migrate — There are no fixed crawl rates. Therefore, the time to completion of your migration will vary from website to website, depending on its size. Migration takes place on a per URL basis.
- Semantic Markup — Changing the semantic markup to HTTPS is not critical for structured data, but it is recommended to update them to the HTTPS URLs.
- Crawling Rate — John Mueller in one of his follow-up comments confirmed that when they notice a move to HTTPS, they sometimes will try to crawl the website faster than normal. If you find the increase crawl rate using up too many server resources, you can set the crawl rate limit in the Search Console.
PageRank loss — HTTP to HTTPS redirect
One of the most significant insights in the FAQ's was the comment about PageRank. It has long been known that when you use 301 redirects, a small proportion of your PageRank is lost in the transfer. This stems from a Matt Cutts Video back in 2013, in which Matt Cutts said:
The principle behind this has been a factor that has cautioned many webmasters from moving to HTTPS, despite the rankings boost that it offers. Is the loss in PageRank more than the benefit of moving to HTTPS?
We now have a definitive answer; There is no PageRank loss where it involves a direct 301 HTTP to HTTPS redirect, and as such, it is not surprising that it has got SEO's buzzing. John Mueller commented:
Spend days writing & cross-checking a FAQ on HTTPS, and the main topic of comments is PageRank. pic.twitter.com/ySepYhqnM8— John Mueller (@JohnMu) February 2, 2016