Don't waste your time. They are not serious. I've seen this at other Chicago prop firms where applicants are run through the process without a real position being in play. I responded to an online job site posting with cover and resume detailing my vast experience with Chicago firms. They sent automated invite to take 3 day hackerrank assignment. Me, always up to a challenge and happy to demonstrate my abilities, invested in this exercise. This exercise detailed the evaluation rules and their ranking starting with all tests must pass; clean readable design, and efficiency of algorithms. I submitted a solution, well before the deadline, that passed all tests. It was well written with appropriate design patterns given the scale of the problem. It was also appropriately efficient given the scale. Additionally, I discussed in comments how these would change in an 'at scale' solution. I have many years experience in these firms. What we do is not rocket science nor is it brain surgery. I have the experience to know what it is and my submission demonstrated that. My submission exceeded their requirements and I fully expected to receive a technical phone call. What I received was another automated email stating that my submission did not meet the minimum requirements. Its clear that they are running a resume mill and that there is no real opportunity. They exploit an applicant's time to try to garner insight into their competitor's technology and a finger on availability in case they want to push expensive current employees out the door. Bottom line, regardless of position, steer clear of this company.