Your interview experience will most probably vary highly on the language you choose and the libraries you know in that language. Some of their problems are extremely easy to solve in Python but would require way too much work in, for example, C++. I'd suggest you pick Python and brush up on your regex and HTTP libraries.
HTTP request/response replay
The following metrics were computed from 1 interview experience for the Stripe Software Engineer (Internship) role in Slovenia.
Stripe's interview process for their Software Engineer (Internship) roles in Slovenia is extremely selective, failing the vast majority of engineers.
Candidates reported having very good feelings for Stripe's Software Engineer (Internship) interview process in Slovenia.