1. Initial culture fit chat. Chat with an engineering manager about what you’re looking for and your background. 2. Coding exercise. Write a sudoku solver in the language of your choice. I wrote mine in Ruby. You’ll be given specs to drive implementation. The API will have two public methods: 1. Figure out the possible choices for the first empty spot in the grid and 2. Use the first method to get the next choices, iterate through each one, and recursively call this method until a solution is found. 3. System design interview. You’ll be given three questions: 1. Implement a rate limiter. Use redis and say that each redis entry will have a combo key of user ID /minute and the value will be the count of how many times the endpoint was accessed during that minute. You can sum those values for the past 10 minutes to see if a user has made over 1000 requests in the past 10 minutes. 2. Implement a google search. Talk about denouncing for the front end and talk about trigrams for the backend. Make sure you can talk about trigrams intelligently. They might ask about location based results. Talk about geofencing. 3. Design a Facebook feed page. Don’t say to hit a bunch of different endpoints. In hindsight, I should have said one endpoint can query all the relevant DB tables for the different info (posts, usernames, profile pictures, comments), but I was nervous because you’re asked to design whole systems in the span of ~30 minutes. Everybody I interacted with was really nice. I just have no idea what people are looking for in system design interviews. They say they ask you three system design questions so in case you “get one wrong” you can still redeem yourself. But they don’t make it clear what constitutes a success vs a failure.