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Experts' analysis in detail
Technical Analysis of Winicar by Alexandre Madonna
The choice of technologies

Winicar is a used car marketplace, so the site must be able to support a large volume of vehicles to be presented in the form of filterable lists and detailed qualitative files.

When browsing the site, two strong constraints emerge at the technical level:

The ability to provide a smooth user experience on the vehicle listing page(s) (which are intended to be quite visual).
Minimizing loading time (SEO and UX reasons) on detailed car sheets that include very large images to enhance the immersive effect
Winicar made an interesting choice by opting to use the open source framework Angularjs to structure its client side. This framework, which has become the most popular in its category, is notably used to improve the rendering and fluidity of web applications or very visual sites with animations and a lot of user interactions.

At Winicar it seems like a good choice to optimize the UX of the list chinese overseas africa database of cars to buy (which constitutes the heart of the site), in particular by allowing the filters to be quickly updated on a large volume of vehicles.

Furthermore, most of the images (especially those of cars) are hosted on a separate server to improve their loading time, whether on lists or files.

The Performance

To measure performance on Winicar, we will select a few major and representative pages of the site: the homepage, the list of vehicles and a detailed sheet of a car for sale. We will then test these pages with performance measurement tools (among other indicators) such as:

Google PageSpeed ​​Insight
Pingdom Website Speed ​​Test
GT Metrix
Dareboost
In terms of loading time, the results of Pingdom Website Speed ​​Test are good since, for a test carried out from a server located in Europe, the tested pages load in 1 to 2 seconds. The number of requests executed is also good (around 50 to 60).

But when we look at the PageSpeed ​​scores given by Google's tool, we realize that he is not entirely satisfied:

On the homepage and the list of vehicles the PageScore is between 50 and 60 on both desktop and mobile, a rather average score.
On the vehicle sheet, it even falls around 10!
These bad marks do not come specifically from the overall loading time of the pages but from the fact that Winicar still has some room for optimization on key points:

The first point concerns image optimization. They must be compressed almost everywhere, and especially on product sheets where there are very heavy images (loading a sheet weighs about 10MB with several images at more than 1MB)
On the homepage, some image files can be resized to their display size which will also reduce their weight.
Finally, on product sheets as well as on the vehicle list, images are not cached since they do not have a defined expiration date. A returning visitor must therefore re-download each image even if they have already viewed them.
Miscellaneous remarks

There are traces of a tawk.to script (a tool for chatting with visitors) that is sometimes called. However, I have never found it in the interface during my tests. Is this tool really used? If not, it would be better to remove the call to the script.
A small UX point to mention to finish: on the list of cars, the button to open the filter panel is aligned to the left, with a large screen it is very far from the user's attention zone (on vehicles) and the icon is not very explicit and does not help to locate the filters...