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WHOOP

Mid-sized

WHOOP is a wearable technology company that produces a fitness and health tracking device and subscription service focused on monitoring metrics like strain, recovery, sleep, and heart rate. It is known for its screenless wrist-worn band and data-driven approach aimed at athletes and health-conscious consumers.

4 interview notes · updated Jul 2026

WHOOP·Mobile Engineer·Onsite - System Design / Architecture

Jun 2026
WHOOP mobile engineer interview, system design round. Two pretty stern interviewers and the whole thing felt like they were more interested in watching you squirm under pressure than actually hearing your thought process. Got through it but not cleanly.
  • Design a BLE command handler for a mobile app where commands must be sent sequentially, with each command waiting for the previous response before the next one is dispatched (or timing out).

“This one tripped me up more than it should have.”

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WHOOP·Mobile Engineer·Technical Phone Screen

Jun 2026
Coding round for a mobile engineer role at WHOOP. Pretty short and focused, just one task to build out a small UI screen using MVVM.
  • Implement the rendering logic for a small UI screen following the MVVM pattern.

“Seemed straightforward but the devil is in the details with MVVM.”

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WHOOP·Software Engineer·Onsite - System Design / Architecture

May 2026
Whoop iOS interview, system design round focused entirely on BLE command handling for a wearable. Pretty niche problem that sits somewhere between mobile architecture and embedded systems thinking. Left feeling like I covered the basics but probably undersold the concurrency side.
  • Design a BLE command handler for an iOS app that communicates with a wearable device. Commands must be serialized strictly, with timeout handling, response matching, concurrent enqueueing from multiple app components, and a defined failure policy when a command times out. Walk through your architecture, concurrency model, and how you'd test it.

“This is a meaty one.”

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WHOOP·Mobile Engineer·Technical Phone Screen

May 2026
Tech screen for a mobile engineer role at WHOOP, conducted by a couple of engineers. Pretty interactive and went deep on Swift Concurrency. Nothing unfair, but you need to have actually used it, not just read about it.
  • How does Swift Concurrency work, and what are the key concepts you use when building concurrent features in iOS?

“They went pretty deep here, not just async/await basics but actual mechanics.”

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