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Meta interview notes, page 238 of 238

FAANG / Big Tech

Most of these Meta write-ups come from Software Engineers (1,194), then Data Scientists (489) and Product Managers (453). The most reported rounds are the technical phone screen (1,190), the product sense round (466), the system design round (255) and the behavioral / leadership round (205).

2377 interview notes · updated Jul 2026

Meta·Software Engineer·Onsite - System Design / Architecture

Jul 2026
Meta system design round for a software engineer role. The whole session was built around one meaty question about building a robust API endpoint, and it went deeper than I expected across a lot of dimensions.
  • Design the full validation and error-handling strategy for an API endpoint that computes the top-K most frequent values from a user-submitted array. Cover input validation, auth, rate limiting, idempotency, error codes, partial failures, timeouts, retries, observability, and graceful degradation for bad or oversized payloads. Include example API contracts and error response shapes.

“This question sprawled in every direction and I kept second-guessing whether to go broad or deep first.”

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Meta·Data Scientist·Technical Phone Screen

Jul 2026
Meta data scientist interview with a stats-heavy question about evaluating a marketing campaign's CTR. The whole thing was basically a hypothesis testing deep dive, which I expected but still found myself fumbling through parts of it.
  • You're told a marketing campaign has a 4.2% click-through rate. Leadership wants to know if that's good or bad. How do you formally set up the hypothesis test, choose the right statistical test, and figure out what additional data you need? Walk through computing a p-value and confidence interval, and explain both statistical and practical significance.

“This question has a lot of layers and I didn't pace myself well.”

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Meta·Data Scientist·Technical Phone Screen

Jul 2026
Meta DS technical screen, basically one big SQL problem broken into three parts. The schema wasn't too scary but the overlap logic and P90 requirement made it genuinely hard to keep in one clean query. Left feeling like I got maybe 70% of the way there.
  • Given a call participation schema with overlapping time intervals, compute peak concurrent participants per call while excluding test users and users from a specific email domain. A call qualifies as a 'group call' if its peak concurrency reaches at least 3.
  • For each calendar day in a given date range, return the total calls started, number of group calls, and the 90th percentile of peak concurrency, filtering to calls where group calling was enabled.
  • Return the top 3 calls by peak concurrency that started on a specific day, including call metadata and the first timestamp within the first 10 minutes of the call when concurrency first hit 3. Return NULL if it never reached 3 in that window.

“The filtering part was fine, just a join on users with a couple of WHERE conditions.”

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Meta·Software Engineer·Technical Phone Screen

Jul 2026
Meta SWE coding round, pretty standard interval problem. Nothing too crazy but the edge cases around touching endpoints tripped me up more than I'd like to admit.
  • Given a list of closed intervals, merge all overlapping ones (including those that touch at endpoints) and return the resulting sorted list.

“Sort first, then sweep.”

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Meta·Software Engineer·Technical Phone Screen

Jul 2026
Meta SWE coding round, one LeetCode problem with a complexity follow-up. Pretty standard but the complexity analysis part is where they actually want to see if you know what you're doing.
  • Given two nodes in a binary tree where each node has a pointer to its parent, find their lowest common ancestor. Then analyze the time and space complexity of your solution.

“I got the core idea pretty quickly since I'd seen LCA before, but this variant with parent pointers trips you up if you default to the recursive tree approach.”

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Meta·Data Scientist·Technical Phone Screen

Jul 2026
Meta DS interview focused entirely on a single sprawling experiment design question about network interference and spillover effects. Dense, technical, and pretty humbling if you haven't thought hard about SUTVA violations before.
  • A new social feature might cause network spillovers (like hashtag following or invite prompts spreading between users). Design an experiment that can separately measure direct effects on treated users and indirect spillover effects on their neighbors, covering the full design, estimands, power calculations, analysis approach, guardrails, and what happens when the graph changes mid-experiment.

“This was basically six questions wrapped in one.”

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Meta·Software Engineer·Onsite - System Design / Architecture

Jul 2026
Meta system design deep dive, infrastructure focus. The whole thing was structured around one project from your resume and they just kept pulling threads until something unraveled.
  • Walk me through the most impactful infrastructure project on your resume, starting with the problem statement, constraints, stakeholders involved, and how you defined success.
  • Describe the high-level architecture of that project, including key components, your data model, and any critical algorithms or APIs you built or relied on.
  • What were the scale requirements for this system? Walk through QPS, latency targets, storage needs, your SLOs, and how you approached capacity planning.
  • Tell me about the most serious incident or failure you experienced with this system. What happened, how did you mitigate it, and what did the postmortem surface?
  • What were the quantified results of this project, and if you had three more months to keep working on it, what would you change?

“This is where I should've been more precise about the stakeholders piece.”

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