Roblox Software Engineer interview questions

79 Software Engineers have shared notes from their Roblox interviews, with the questions they were asked in each round. That is 56% of the 142 Roblox interview notes on Screna AI.

79 Software Engineer interview notes

Roblox·Software Engineer·Onsite - Multi Round

Aug 2026
Did a power day at Roblox for a SWE intern role, three rounds back to back: two coding and one behavioral. Both technical rounds went pretty well overall, though I fumbled the output logic on the second one before catching it. Now sitting at 17 business days post-interview with no decision, which is making me spiral a little.
  • Solve an algorithmic problem where the interviewer had their own solution in mind, and defend your approach if it differs.
  • Given an unfamiliar problem, derive an algorithm from scratch, implement it, and handle edge cases correctly.
  • Behavioral questions about past experiences and motivations.

“Came up with something the interviewer hadn't considered.”

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Roblox·Software Engineer·Online Assessment (OA)

Aug 2026
Roblox OA was a bureaucratic nightmare before a single question even loaded. Between multiple face verification loops, a laptop that sounded like it was about to take off, and nearly three hours of IQ-style games, the only bright spot was the coding section.
  • Complete a coding challenge as part of the online assessment.

“The one section I actually felt okay about.”

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Roblox·Software Engineer·Onsite - System Design / Architecture

Jul 2026
Roblox system design round focused entirely on rate limiting, which sounds straightforward until they start layering on multi-dimensional constraints and distributed deployment concerns. Pretty deep dive for a single question.
  • Design a sliding-window rate limiter that enforces a global cap of R requests within any rolling T-second window. Cover the public interface, data structures, time resolution, and time/space complexity.
  • Extend the rate limiter so each request carries a userId and userExperience field, and both dimensions are rate-limited independently and concurrently. How do you structure keys and counters without double-counting across dimensions?
  • How would you evict stale state from the rate limiter efficiently as the window slides forward?
  • How do you deploy and scale this rate limiter in a distributed environment? Address sharding, coordination between nodes, clock skew, and idempotency.
  • How would you test this rate limiter for correctness, including burst traffic, boundary timestamps, and window rollover edge cases?

“I started with a circular buffer approach and talked through how a true sliding window differs from fixed-window bucketing.”

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Roblox·Software Engineer·Technical Phone Screen

Jul 2026
Roblox coding round with one meaty grid simulation problem. Two phases to implement, which sounds manageable until you're actually in it trying to keep track of what counts as a run and then simulating gravity correctly.
  • Given an m x n grid of single digits, first find all horizontal or vertical consecutive runs of the same digit with length 3 or more, returning each as [row, col, length] sorted top-to-bottom then left-to-right. Then remove all cells belonging to those runs, let the remaining digits fall down within their columns, and fill the top with zeros. Return the final grid.

“The two-phase structure is what gets you.”

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Roblox·Software Engineer·Technical Phone Screen

Jul 2026
Roblox technical phone screen for a software engineer role. The problem was a digit-sum bucketing question with some spicy follow-ups that I wasn't fully prepared for.
  • Given two integers low and high (inclusive), define s(x) as the sum of the digits of x. Group every integer in [low, high] by its digit sum, and return the size of the largest group. What's your algorithm and its time and space complexity?
  • When the range high minus low is extremely large, can you avoid iterating over every integer in the range?
  • How would your approach change if the numbers were represented in an arbitrary base b (where b can range from 2 to 36)?

“The core problem isn't bad.”

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Roblox·Software Engineer·Online Assessment (OA)

Jul 2026
Took the Roblox OA and now I'm sitting here second-guessing everything. The CodeSignal was surprisingly easy but the simulation problems, especially the Mars drone one, did some damage. Roblox really loves 2D arrays right now.
  • Factory simulation problem: navigate and manage a factory environment programmatically.
  • Mars drone simulation: write functions to control a drone navigating across maps, then apply those functions under test conditions.
  • Matrix traversal or manipulation problem (two separate questions), with the second requiring optimization from a naive to a more efficient solution.

“Spent a decent chunk of time on this one and I'm still not sure how I did.”

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Roblox·Software Engineer·Onsite - System Design / Architecture

Jul 2026
System design round at Roblox for a software engineer role, focused entirely on designing a matchmaking system for a multiplayer game. Covered a lot of ground in one question, which was both interesting and a bit overwhelming.
  • Design a matchmaking system for an online multiplayer game. Walk through requirements like game modes and party size, your high-level architecture, how you'd handle skill-based bucketing and region sharding, how you'd balance match quality against wait time, what happens when players go stale or drop out of queue, fairness and anti-smurf measures, and how the system scales to millions of concurrent players.

“This is a beast of a question.”

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Roblox·Software Engineer·Onsite - System Design / Architecture

Jul 2026
System design round at Roblox for a software engineer role, focused entirely on building a like/unlike system that could handle massive write throughput. Pretty deep dive, they pushed hard on the tradeoffs.
  • Design a Like/Unlike system that can operate at scale, supporting operations like liking a post, unliking it, fetching like counts, checking if a user has liked something, and showing a user's liked posts feed.

“This one went longer than I expected.”

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Roblox·Software Engineer·Onsite - System Design / Architecture

Jul 2026
System design round at Roblox for a software engineer role, focused entirely on designing a Likes system from scratch. The depth they expected was pretty serious, covering everything from schema choices to handling celebrity items under load.
  • Design a Likes system that supports liking/unliking items, checking if a user has liked something, listing a user's liked items with pagination, and fetching total like counts per item. Focus on scalability and data schema.

“This one sprawled fast.”

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Roblox·Software Engineer·Technical Phone Screen

Jul 2026
Roblox SWE interview with a system design coding question focused on rate limiting and bot detection. Pretty meaty for a single problem, they wanted you to think through the whole thing from data structures to memory management.
  • Design and implement an IP-based bot detection system. It should track how many requests each IP makes within a sliding time window, flag IPs that exceed a threshold, and periodically clean up stale data to keep memory bounded. Implement record(ip, timestamp) and isBot(ip, timestamp).

“I went straight for a per-IP deque of timestamps, which felt right.”

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