I recently started (and flunked) the Instacart interview process for a Senior iOS position and wanted to recap the experience for the next person coming down the chute.

In my case, I didn’t actually go on site, as I was interviewing from another part of the U.S.

Prior to my technical interview, I did get a quick overview of the company's current state:

• 400 people in corporate, with 200 in engineering.
• The mobile team is only 16, with 8 doing Android and 8 doing iOS.
• There are two apps that matter: the consumer app and the shopper app, led by Technical Lead Managers (TLMs), divided into vertical teams organized by product or feature.

Like other iOS engineer interviews you might find here on Glassdoor, I was given the “Grocery Challenge” app project to do. Unlike other interviews, they gave it to me as a project to complete within 45-60 minutes as a challenge during a Zoom video/audio call with two other engineers listening in.

The “pair programming” phone call was somewhat weird all around. The coordinator sent me the exact time when I’d be doing the exercise only about 12-18 hours before it was scheduled to happen.

The HackerRank link did not give actual requirements or specific implementation details until after I clicked on the “Start Interview” timer button. However, there was a Google Doc link on the page to an Xcode “starter project.” After looking through it, I was able to divine some of the details about the project Instacart wanted me to code.

So when the actual call happened the next morning, I had about 75% of the app already ready to go. I tried to implement some additional implementations/features while the two engineers sat on the line and watched me do my work. One engineer was somewhat talkative, and the other was utterly silent and would only speak up when I said “hello” to her.

After the 60-minute call finished, I was given 30 minutes to clean, finish, and submit everything through HackerRank. There really wasn’t any time for me to ask meaningful culture or tech stack questions about the Grocery or Shopper apps while I was trying to wrap my head and hands around the coding project that was on their (and my) screens in front of me.

The next day, I got the standard disappointing “thanks but no thanks” rejection email from the recruiter with the usual lack of explanation.

I thought the interviewers would have been encouraged or pleased that I had researched the code and had a pretty good implementation just about ready to go even before the actual instructions were given and the phone call started. Apparently, these Instacart engineers have seen their Grocery Challenge project so often (both as this 45-60 minute challenge and as a 4-5 hour “homework assignment”) that they are looking for perfect, production-quality code. I think this would be a very unrealistic and unreasonable challenge for all but the most-prepared-for-interviewing candidates, which is why I think providing more details here is fair.

Perhaps I would have done somewhat better had the challenge been given as a 24-hour homework assignment instead of the one-hour awkward phone conversation. Perhaps it'll be better for you!

Hopefully, my experience flunking the interview process at Instacart will help you to properly prepare for yours. If you find any of my information useful, please let me know by clicking on the “helpful” link below. This helps to motivate me to be as detailed as possible in my interview reports.

Good luck to you!

Build a Shopper Grocery Challenge

The app should display a question, its multiple-choice options (images), allow the shopper to select an image, and submit it.

Requirements:

• Show the question's query and four answer options.
• The shopper should be able to select an answer and submit it.
• Once submitted, provide feedback if the answer was correct or incorrect.