flipster

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Flipster is a cryptocurrency derivatives trading platform that offers perpetual futures and other digital asset trading products. It is known for providing a fast, user-friendly interface aimed at both retail and professional crypto traders.

5 interview notes · updated Jul 2026

flipster·Software Engineer·Onsite - System Design / Architecture

Jul 2026

Two system design questions back to back at Flipster for a software engineer role. One was the classic snowflake-style ID generator and the other was a parking lot OOP design. Pretty standard senior-level stuff but there's a lot of surface area to cover in a single session.

Design a distributed service that generates globally unique 64-bit integer IDs at very high throughput, with time-ordered output and support for sharding across many nodes.
Design a parking lot management system with multiple levels, different spot types, ticketing, fee calculation, and concurrent spot assignment.

“I went straight to the bit layout: timestamp in the upper bits, worker ID in the middle, sequence counter at the bottom.”

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flipster·Backend Engineer·Onsite - System Design / Architecture

Jun 2026

Flipster system design round, focused entirely on building a distributed ID generation service. Pretty deep technically, they wanted specifics on almost every component rather than a high-level sketch.

Design a distributed service that generates unique 64-bit IDs at high throughput, covering bit layout, collision avoidance across nodes, clock skew, sharding, sortability, and failure scenarios like clock rollback or duplicate machine IDs.

“This is basically the Snowflake ID question and I knew the shape of it going in, which helped.”

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flipster·Software Engineer·Onsite - System Design / Architecture

Jun 2026

Flipster system design round focused entirely on a parking lot problem. Went deeper than I expected, covering concurrency, EV charging, and reservations on top of the core OOP stuff.

Design a parking lot system covering the class hierarchy (ParkingLot, Level, Spot, Vehicle types like Car, Truck, Motorcycle, and a Ticket class), spot assignment logic, and the full entry and exit flow including payment.
How would you handle concurrency at multiple entry and exit gates simultaneously?
How would you extend the design to support multi-level parking structures?
How would you add support for electric vehicle charging spots?
How would you support advance reservations in this system?

“I started with the Vehicle hierarchy and worked outward, which felt natural but I spent too long on the OOP side before getting to spot assignment.”

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flipster·Software Engineer·Technical Phone Screen

Jun 2026

Flipster SWE interview had at least one coding round with a classic stock profit problem. Pretty standard stuff but the edge cases are where they probably separate people.

Given an array of daily stock prices, find the maximum profit you can make from a single buy-then-sell transaction. Return 0 if no profit is possible.

“Knew this one the second I read it.”

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flipster·Software Engineer·Technical Phone Screen

May 2026

Had a technical screen at Flipster that was pretty much one coding question the whole time. Classic stock problem, nothing too exotic, but the O(1) space constraint is where they're actually testing you.

Given an array of daily stock prices, find the maximum profit from a single buy-then-sell transaction. Return 0 if no profit is possible. Must run in O(n) time and O(1) space.

“The question itself is pretty standard but I fumbled around with a brute force explanation first before they nudged me toward the linear approach.”

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