Founder here, you showed up unprepared to basic IT / Computer science questions (as in "what is a hashmap" or some basic HTTP principle.. just for clarity to whoever may be reading) justifying that you had forgotten what you knew before having just returned from this immense lifetime vacation because "you're still young.." and that got to my nerves as in "how about you study then before showing up". Tell me something about Elasticsearch 6 that i dont know is not a possible question at our interview, we well know its a complex topic. I believe you're mixing up memories of 2 questions. Anyway, its regrettable we ended up in negative terms and i am not happy that you had a bad personal experience. Since this happened we have put extra layers (e.g. automatic coding tests) to make sure that by the time there is a direct interview there is a better fit on expectations.