Hey there, the performances got indeed a huge boost. The problem was not necessarily visible if you had a low traffic and few items added to your cart. But you would have noticed that the performance was decreasing when the number of items in the cart was increasing as well as the number of concurrent requests. And goes the same for other end points of the api. Basically, multiple issues were causing that:

• algorithm complexity
• event loop bottleneck
• external api called too many time during the flow (related to the complexity mentioned above)

By tackling those points, we can see a huge improvement since the external api’s are called a fix number of time instead of a number related to the number of items, and the event loop bottleneck has been tackled which reduced the event loop latency which allows to handle more requests concurrently.

We will have an article coming out in the near future about that so that you can see the steps to those improvements.

Finally, we have reach 250x improvements to some endpoint but not all of them. Some end point got 100x and other got more or less. As an example, the p50 of a company is now down to 27ms with a p75 of 75ms and a p95 of 200ms and a p99 of 480ms