I applied online. The process took 3 months. I interviewed at Stripe in Jan 2019
Interview
1. hackerrank (difficulty really depends on the problem they send you), and their test-cases are sometimes wrong/unexpected.
2. technical screening (camera + screenshare), this one wasn't hard.
3. on-site with 3 "official" interviews + some unofficial talks
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.
There was a recruiter call where they told me what to expect for the next couple rounds. I had a call with the hiring manager and technicals with 2 other engineers.
I applied and got an interview offer in about 2 weeks. I interviewed with someone from the US even though i applied for Bucharest. A bit of introduction and HR style questions in the beggining, followed by 2 problems.
The first step is a HackerRank challenge, typically 60 minutes long, consisting of one question broken into 3 parts/sub-tasks. The question is implementation-heavy rather than a typical dynamic programming or graph puzzle.