I just went through the entire interview sequence for a Senior/Lead iOS Developer role over at DraftKings and thought it would be useful to recap how it was and my experience, just to help future candidates coming down the chute.

I spoke with the recruiter three or four times. One time as an introduction, the second time was interview prep for the "virtual on-site," then the last encounter, which I'll talk about at the end of this recap.

All video interviews are done using Microsoft Teams (DK only recently dropped using Zoom for their conference calls), but they still do internal communication via Slack. All technical interviews have HackerRank whiteboards and coderpads available to work with.

The first interview (with a lead dev) is a straight coding session. This was the standard "given an array of customers & total revenue, discounts & their amounts, and types of discounts being offered to customers" problem, which I'll try to detail as completely as possible below. This one seemed to go really smoothly (I just loaded a bunch of arrays and implemented the validation rules and explained myself as I went along), and I got the call the next day inviting me to do the "virtual on-site."

The virtual on-site can potentially eat up four hours out of a business day, but in my case, they split it up: one interview on one day and then the last three on the next day.

The system design interview session basically had the candidate designing an odds provider/serving system for DraftKings players. I dutifully sketched out how I would do it and felt relatively good about the conversation, though apparently the person interviewing me didn't feel the same.

The next interview was covering Team Dynamics with the director (or the guy one level above the hiring manager), and this is where I was asked the standard "are you a team player" and "tell me about when you failed and how you recovered" questions that are part of most behavioral & cultural interviews.

The director did provide much more context about the role I was interviewing for: DK is trying to migrate everything to individual & native SDK's and frameworks (I think delivered via Swift Package Manager) from the legacy (and increasingly difficult to work with) Xamarin codebase.

I recall the director saying the size of the team was five when I spoke with the director; it will be six by the time this recap gets published, and they hope to eventually have at least 9 or 10 developers on the team. The current breakdown was 3 Android, 1 iOS, 1 lead who is doing iOS, and then the new iOS developer that was joining. So with that relatively small number, I'm guessing the director was referring to the Player Account Management team and not to the entire mobile organization.

I got to speak with the hiring manager next, and his topic was a "deep dive" into some project/technical history, where I had to explain some amazing feature I had worked on in the past, how I implemented it, how I interacted with various people (e.g., project managers or product owners, UX/UI designers, backend devs, and then collaborating with Android devs on my team to make sure iOS & Android were behaving the same in parallel).

My last technical interview was the "Object Oriented Design Exercise," and it basically had me implement how to structure how chats would be displayed and the underlying data dealt with. This one ended up being the one that likely got me disqualified, but I'll detail below.

The last day of the week (one day after their internal recap session), the recruiter called me back to give me the official thumbs down. I am very grateful that the recruiter did provide relatively detailed feedback as to where and how I goofed up: the two technical interviews of the "virtual onsite," I apparently didn't provide enough detail or perhaps I sounded shaky. And while I won't console myself with this as an excuse, I still believe I did okay given that this was my first set of hardcore interviews post-pandemic and I've been out of practice for a couple of years.

But hopefully, my experience flunking the process will help you prepare for interview success, especially if you are aiming for a Mobile (iOS) role on the mobile team.

If my notes did help you to prepare for your interview, please let me know by clicking on the "helpful" link below (as this motivates me to try to be as detailed as possible).

For the "Object Oriented Programming" technical interview, I was given a screenshot with two screens. The first view represented a list of chats/conversations with friends (whether 1-1 or group chats). Preferred friends were also selectable in a carousel or collection view at the top of that table view. The other view was an individual chat clicked through from the chat list/table. The individual chat might be with one user or a group. It allows text, embedded emoticons or animated GIFs, and little icons to indicate whether the chat recipient(s) have actually seen the text. Describe how this would be structured and set up.