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eBay interview notes, page 2 of 6

Large Enterprises

Most of these eBay write-ups come from Software Engineers (47), then Product Managers (4) and Backend Engineers (1). The most reported rounds are the technical phone screen (32), the system design round (9), the behavioral / leadership round (4) and the product sense round (4).

53 interview notes · updated Jul 2026

eBay·Software Engineer·Onsite - System Design / Architecture

Apr 2026
eBay system design round for a software engineer role. One question, focused on building a data query system with scalability and consistency in mind. Pretty open-ended, which I wasn't totally prepared for.
  • Design a data query system that can handle peak traffic, scale effectively, and maintain data consistency.

“I started with caching and indexing and felt okay for the first few minutes, but then they pushed on consistency guarantees during high load and I fumbled a bit.”

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eBay·Product Manager·Onsite - Product Sense / Strategy

Apr 2026
PM interview at eBay with a classic build vs. buy question. Not a lot to go on but it's the kind of thing that trips people up if they haven't thought through the tradeoffs before walking in.
  • How do you decide whether to build a solution internally or purchase an existing one?

“This sounds straightforward until you're actually sitting there and realize there are like six different dimensions pulling in different directions.”

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eBay·Software Engineer·Technical Phone Screen

Apr 2026
eBay SWE interview that focused on extending an in-memory file system across multiple layers of complexity. The final piece was a capacity eviction problem that required careful thought about ordering and data structures.
  • You're given an in-memory file system that already has basic file operations and per-user storage tracking. Implement an updateCapacity(userId, newCapacity) function that, if the new capacity is too small for the user's current files, evicts files from largest to smallest (alphabetical name as tiebreaker) until the total fits, and returns the count of evicted files. Return None if the user doesn't exist, 0 if no eviction is needed.

“The base file system stuff was fine, I'd seen similar problems before.”

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eBay·Product Manager·Onsite - Product Sense / Strategy

May 2026
PM interview at eBay, just one question but it was a meaty one about metrics for a new e-commerce launch. Pretty standard product analytics territory but easy to fumble if you go too broad.
  • If you just launched a new e-commerce website, what metrics would you track and why?

“I went straight to conversion rate and GMV which felt right but then I realized I was skipping the funnel entirely.”

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eBay·Software Engineer·Technical Phone Screen

May 2026
eBay coding interview with a grid simulation problem that felt deceptively tricky once gravity kicked in. Not a lot of context given upfront, just the problem and a blank screen.
  • Given an n x n grid of colored balloons (represented as integers), simulate a chain reaction: find all balloons with at least two neighbors of the same color and remove them, then let the remaining balloons fall down due to gravity. Keep repeating until no more balloons can explode. Return the final grid state.

“The BFS/flood-fill part I got through okay but the gravity step tripped me up more than I expected.”

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eBay·Software Engineer·Technical Phone Screen

May 2026
eBay SWE interview that extended a file system design problem into compression territory. Pretty focused on state tracking and edge cases, not just the happy path.
  • Extend a file system implementation with compressFile(name) and decompressFile(name) methods. compressFile should halve the file's size and return false if the file doesn't exist or is already compressed. decompressFile should restore the original size and return false if the file doesn't exist or isn't currently compressed.

“The size halving part was easy.”

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eBay·Software Engineer·Technical Phone Screen

May 2026
eBay coding round for a software engineer role, basically one meaty question about implementing and testing a bitmap block allocator. The question had more layers than I expected once they started asking about edge cases.
  • You're given a BitmapBlock class that manages a fixed-size bitmap of allocation slots with methods to allocate contiguous blocks, find free contiguous blocks, and count fragmentation holes. Write a test driver (main function) that exercises the class end-to-end, including failure cases like overlapping allocations and a fully-allocated bitmap. Then explain what edge cases your driver covers.

“I spent too long on the happy path and nearly forgot to test the failure cases until they nudged me.”

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eBay·Software Engineer·Technical Phone Screen

May 2026
eBay software engineer coding round, one problem the whole session. The problem looked like a simple mapping exercise but the edge cases around reuse and limit tracking made it trickier than expected.
  • Write a function that assigns ads to browser positions for a single user, given a list of positions, a list of candidate ads with per-user display limits, and the user's current ad display counts. The function should randomly assign eligible ads to positions, avoid duplicate assignments when possible, allow reuse only when limits still permit it, increment counts on each assignment, and return both the assignment map and the updated state.

“My first pass totally ignored the reuse case.”

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eBay·Software Engineer·Technical Phone Screen

May 2026
eBay coding round, one algorithmic problem the whole session. Not a brutal interview but the question had enough edge cases to trip you up if you weren't careful with your indexing.
  • Given an integer array, find the longest contiguous subarray of even length where the sum of the first half equals the sum of the second half. Return the length or the subarray itself.

“I jumped straight to brute force and the interviewer let me run with it for a bit before nudging me toward prefix sums.”

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eBay·Software Engineer·Onsite - Behavioral / Leadership

May 2026
eBay software engineering interview with a project deep-dive question. Pretty standard behavioral round but they pushed hard on specifics.
  • Tell me about a project you worked on that had significant impact or scale. Walk through the problem, how big it was (users, revenue, system size, org reach), what you personally did, the trade-offs you navigated, and what the measurable outcome was.

“This is the kind of question where you think you have a good story until they start peeling it back.”

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