Meta Interview Questions — Page 55

Meta·Data Scientist·Technical Phone Screen

Apr 2026

Meta DS interview focused entirely on a product experiment case around group video calling. Four sub-questions in one scenario, which felt like a lot to cover in one sitting. The depth expected was real.

Before deciding whether to build group video calling, what data sources or internal reports would you look at first?
What single metric would you use as the primary success indicator for group video calling, and why that one?
How would you determine the right maximum number of participants allowed in a group call?
Walk through how you'd design an A/B test for this feature, including control vs treatment setup, how you'd define the metric, and the statistical considerations you'd account for.

“I went straight to usage patterns and competitor benchmarks, which felt right, but I forgot to mention support tickets or qualitative feedback.”

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Meta·Software Engineer·Onsite - System Design / Architecture

Apr 2026

Meta SWE onsite design round. The whole session was basically one massive object-oriented system design problem disguised as a coding question. Way more edge cases than I expected going in.

Design and implement a BankSystem class from scratch that supports creating accounts, depositing funds, making payments between accounts, initiating transfers with holds, accepting transfers within an expiry window, and merging customer identities. Walk through your data models, API return values, error handling, and the time/space complexity of each operation.

“This one ate the entire interview.”

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Meta·Product Manager·Onsite - Product Sense / Strategy

Apr 2026

Meta PM interview with a single product improvement question about Houseparty. Not much context to go on but it's a pretty classic Meta product sense prompt.

How would you improve Houseparty?

“Houseparty is kind of a weird one to get because Meta actually shut it down, so there's a layer of awkwardness where you're improving a dead product.”

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Meta·Data Scientist·Technical Phone Screen

Apr 2026

Meta DS interview with a stats-heavy question on comparing two models using a hypothesis test. Pretty much one focused problem but they wanted the full treatment, not just a gut answer.

Model A had 90 successes out of 100 users and Model B had 85 successes out of 100 users. Based only on this data, can you say Model A is better? Walk through the statistical test, your hypotheses, the math, and what the result actually means.

“I jumped straight to 'yes A is better' before they even finished the question, which was obviously wrong.”

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Meta·Software Engineer·Onsite - System Design / Architecture

Apr 2026

Meta data engineering system design round, basically one massive question that covered everything from ingestion to SLAs. The scope was brutal and I kept second-guessing whether to go deep on one area or stay broad.

Design a complete data platform that handles both daily batch and near-real-time streaming for product analytics, covering everything from ingestion through to serving layer.
How would you handle idempotency, deduplication, and late or out-of-order events in a streaming pipeline?
Walk me through your approach to table partitioning and clustering for a large-scale analytics workload.
When would you use an append-only pattern versus an upsert or merge pattern, and how do you handle slowly changing dimensions?
How do you approach backfills in a production data pipeline, especially when the pipeline has already been running for a while?
Describe how you'd handle orchestration, dependency management, and failure recovery across a complex multi-step pipeline.
How would you compute daily, hourly, and rolling-window metrics efficiently at scale?
What data quality checks would you implement and how do you define and enforce SLAs on a data platform?

“This was basically the whole interview compressed into one prompt.”

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Meta·Software Engineer·Technical Phone Screen

Apr 2026

Meta SWE interview centered on binary search with a peak-finding problem. The 2D follow-up was the real curveball and apparently shows up more in onsite rounds than phone screens.

Given an array where no two adjacent elements are equal, find the index of any peak element. A peak is greater than both its neighbors, and out-of-bounds positions count as negative infinity. Solve it in O(log n).
Follow-up: extend the peak-finding approach to a 2D matrix. Find any peak element where the value is greater than all its adjacent neighbors.

“The core logic clicks pretty fast once you think about it: if the element to the right of mid is larger, there has to be a peak somewhere in that direction, so you go right; otherwise you go left and include mid.”

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Meta·Machine Learning Engineer·Technical Phone Screen

Apr 2026

Meta ML coding round where they handed me a text classification task and expected me to walk through the whole pipeline from data loading to deployment. More involved than I expected for a single session.

Fine-tune a pretrained transformer model (such as DistilBERT or BERT) using HuggingFace to classify text as harmful or not harmful. Walk through the full pipeline: loading the dataset, tokenizing, setting training arguments, evaluating with accuracy/precision/recall/F1, and how you'd deploy the model.

“This was basically the whole interview compressed into one prompt.”

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Meta·Software Engineer·Technical Phone Screen

Apr 2026

Meta software engineering interview with two algorithm problems back to back. The questions weren't unreasonable but the depth they wanted on edge cases and complexity analysis was pretty serious. Felt more like a design conversation than a pure coding screen.

Implement a fast exponentiation function pow(x, n) that runs in O(log |n|) time using exponentiation by squaring. Handle edge cases like negative exponents, x = 0, n = 0, and very large exponents. Also discuss iterative vs. recursive approaches and numerical precision concerns.
Given a string of lowercase letters and parentheses, remove the minimum number of parentheses to make the string valid. Return any valid result. Implement an O(n) solution and compare a stack-based approach to a two-pass marking approach, justifying why your removal count is minimal.

“I jumped straight to the recursive version and it went fine, but then they asked me to do it iteratively and I fumbled for a bit.”

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Meta·Software Engineer·Online Assessment (OA)

Apr 2026

Meta coding screen, the kind with multiple levels that build on each other. Started manageable and got complicated fast once TTLs and timestamped reads entered the picture.

Design an in-memory key-field-value store that supports full history tracking per (key, field) pair, and implement a GET_AT_TIMESTAMP operation that returns the value visible at a given time.
Add COMPARE_AND_SET and COMPARE_AND_DELETE operations that only succeed if the current value matches the expected value provided by the caller.
Extend the store to support per-record TTL with timestamped expiry, and ensure consistent semantics when TTL interacts with timestamped reads and compare-and-set operations.

“The base store wasn't bad, I've done enough of these.”

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Meta·Software Engineer·Technical Phone Screen

Apr 2026

Meta SWE coding round with a randomized max index problem. Pretty standard algorithmic question but the random selection twist is where people tend to slip up.

Given an integer array, find the index of the maximum element. If multiple elements share the maximum value, return any one of their indices at random.

“The naive pass to find the max first and then collect all matching indices works fine, but I kept second-guessing whether they wanted a single-pass solution.”

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