Redirection Statistics of the Alexa Top 50 Sites

We were asking a question at work about whether it would be useful to prefetch http://www.url.tld, https://url.tld or https://www.url.tld if a user browses to http://url.tld.

I did a study on the sites ranked in the Alexa Top 50 to see how often a prefetch like that would be useful. In other words, I attempted to count how often a site, bare.tld, from the Alexa Top 50 redirects to www.bare.tld and/or whether the redirection changes protocols from HTTP to HTTPS.

In order to make the study easier, I only considered those redirects done with the HTTP/S headers. In other words, if the connection will be redirected by some JavaScript in a page, those redirections are not reflected in these stats.

Here are the results:

1. 32 of the 50 (64%) redirect from bareurl.tld to www.bareurl.tld
2. 37 of the 50 (74%) redirect from http to https
3. 27 of the 50 (54%) do both

Here is the data, if you want to take a look at it yourself.

Update: As it turns out, some redirection behavior is User-Agent-String (UA String) specific. The default UA String in curl is curl/7.58.0 and using it gives the results shown above. If, however, you specify a more reasonable UA String (Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:69.0) Gecko/20100101 Firefox/69.0), the results are (slightly) different:

1. 32 of the 50 (64%) redirect from bareurl.tld to www.bareurl.tld
2. 41 of the 50 (82%) redirect from http to https
3. 31 of the 50 (62%) do both

Notice that there is no change in the number of sites that redirect from bareurl.tld to www.bareurl.tld but there is an increase in the number of websites that do redirects for secure HTTP.

Data for these results are available here.