I have been a Mettl employee for 2 years. Aptitude test will be conducted on their own platform, where in you might be given to create an entire program (create your own libraries, classes, codes etc), or they might ask you to complete a given code (this depends on your experience level). It can be tough, and/or it can be easy. You may have multiple levels of such coding aptitude tests, depending again on your experience level. You may also have to appear for a psychometric test, through which they’ll try to figure out your personality, and decide if you indeed can be a part of their organization. They’ll expect clarity of thoughts and communication from you.
However, I don’t support the company’s working culture and ethos. I have had an absolutely depressing time down there. I had joined the company looking at their IIM-IIT resource pool, only to later realize that it was all a mirage. I have seen some amazing employees being asked to leave, or who have voluntarily left, just because of the cheap politics being played in the name of running a startup. They do have a breezy atmosphere, and CEO will personally chat with you occasionally, but that’s about it. You will not understand why a process is functioning the way it is presently, and you’ll always “under-perform” in their employee performance reviews. Have a look at the company’s glassdoor reviews, and funnily, you’ll find all the “positive” reviews literally bad-mouthing the employees/ex-employees who’ve written negative (or in my words, brutally honest) reviews about the company. Anyways, I seem to digressing from the topic.