Amazon’s mobile site remains among the fastest, even with increased traffic during its Prime Day shopping event.

The Walgreen Co. got bumped off the Internet Retailer Mobile Performance Index top 10 list for the month of July.

The index ranks the speed of Internet Retailer’s Top 100 retailers’ mobile home pages from July 4-18, based on data provided by digital performance analytics company Catchpoint Systems Inc. Catchpoint provides Internet Retailer with two monthly site performance indexes: one for mobile sites and one for desktop sites.

Walgreens, No. 37 in the Internet Retailer 2017 Top 500, ranked No. 39 on the July index, and its mobile site loaded, on average, in 2.98 seconds during this two-week time period in July. On the June index, Walgreens ranked No. 1 and loaded in 0.82 seconds.

The reason for the more than 2-second slowdown is an increase in the number of images and hosts, a Catchpoint spokesman says. Walgreens did not respond to a request for comment.

advertisement Inc.’s shopping sales event Prime Day also fell within this mid-July time period. Even with the increased web traffic during this period, Amazon (No. 1 in the Top 500) maintained a speedy mobile site, and  improved its mobile site speed during the two-week period.

Amazon’s site loaded, on average, in 1.31 seconds and ranked No. 2 on the index, up from No. 3 on the June Mobile Performance Index when its mobile site loaded in 1.35 seconds. What’s more, Amazon’s traffic on Prime Day (Tuesday, July 12) increased 49.1% compared with a previous Tuesday, June 27, which fell during a non-holiday week. The Tuesday immediately preceding Prime Day was July 5, which followed the Independent Day holiday and thus may not have been representative of normal traffic.

For the two weeks of July 4-18, the Top 100 retailers’ average load time was 3.40 seconds compared with 3.44 seconds the previous month. The average page weight was 2.19 megabytes compared with 2.24 megabytes the previous month, and the average number of hosts was 47, the same as the previous month. The average number of items was 152 compared with 151 a month ago.


The 100 sites averaged 99.48% available July 4-18 compared with 99.80% available June 5-18. These are the 100 leading North American retail sites by 2016 online sales , according to Internet Retailer’s

Catchpoint monitors each website’s home page with measurements taken from Catchpoint’s in-country or in-region monitoring nodes, at intervals of five minutes for two weeks each month. Backbone monitoring nodes are the locations of Catchpoint’s devices that are near data centers operated by the main internet service providers that provide service to a city. The nodes simulate end-user contact with each website. Catchpoint monitors webpage load time, availability, hosts and items.

Here is how each of those four metrics is defined:

Webpage load time: The time it takes for enough page elements to load for a consumer to begin interacting with a page, such as searching, tapping or scrolling. From a consumer point of view, the time it takes for the progress bar or spinning wheel to stop.


Availability: The percentage of time during the two-week test week that the site can be successfully reached by a consumer.

Host: Any domain that delivers data, content or services over the internet to the site.

Items or Requests: Webpage components, such as files or images that a page loads from internal and external hosts or domains. These can include PDFs, PNGs, JPEGs and GIFs.