Problem: Universal Product Recommendations Due to Missing Endpoint Authorization
While working on the recommendation section, it turned out the system returned identical sets of recommended products to every user (both logged in and anonymous). The problem stemmed from lack of authorization on the API side - the recommendation endpoint didn't recognize who the client was (missing token/user identifier), so it returned globally most popular products.
Analysis and Solution
I implemented mandatory authorization for recommendation endpoint requests. After changes, every API request is identified - if the user is logged in, their token is passed, if anonymous - a temporary session identifier is generated for preference tracking purposes. This change, of course, only applied to clients who consented to cookie storage.
Thanks to this, the recommendation system (based on Recombee) is able to return personalized products - both for returning clients and new users.
Result
After implementing the change, the recommendation section began displaying actually matched products, which translated to a CTR/conversion to purchase action increase of 1400% from 0.2% to 2.8%, considering two weeks before and after implementing the change.
