Meta Interview Questions — Page 231

Meta·Software Engineer·Technical Phone Screen

Jul 2026

Meta SWE coding round, one algorithmic problem about building target sums by inserting operators between numbers. Pretty focused session, just the one problem but with enough depth to keep you busy.

Given a list of integers and a target value, find how many ways you can insert '+' or '-' operators between the numbers (or no operator at all, treating adjacent numbers as concatenated) to reach the target sum.

“The 'no operator' part is what gets you.”

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Meta·Data Scientist·Onsite - Behavioral / Leadership

Jul 2026

Behavioral round at Meta for a Data Scientist role, focused on cross-functional collaboration and impact. Pretty standard stuff but the conflict question had some teeth to it.

What is the most impactful project you have led or contributed to, and what was your specific role and the measurable outcome?
Tell me about a time when team collaboration broke down. How did you spot the problem and what did you do to fix it?

“I had a solid project ready for this but fumbled the measurable outcome part.”

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Meta·Software Engineer·Onsite - System Design / Architecture

Jul 2026

Meta data engineering interview, system design round focused on event storage for a consumer app. The question was dense and covered a lot of ground in one shot.

Design a relational schema to store user events for a consumer app. Include table definitions with columns and data types, primary and foreign keys, partitioning and indexing strategy, and sample rows. Also explain your normalization versus denormalization decisions, how you'd handle late-arriving or duplicate events, and how you'd support backfills and incremental fact tables.

“This was a lot to unpack in one question.”

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Meta·Software Engineer·Technical Phone Screen

Jul 2026

Meta coding round with two algorithm problems, both pretty standard but the parentheses one had some edge cases I didn't fully think through in time.

Given the root of a binary tree, return the values of nodes visible from the right side of the tree, ordered top to bottom.
Given a string with lowercase letters and parentheses, remove the minimum number of parentheses to make it valid and return any valid result.

“BFS level-order traversal, grab the last node at each level.”

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Meta·Software Engineer·Technical Phone Screen

Jul 2026

Meta phone screen for a SWE role, and it was pretty much what everyone says it is: Kth Largest, tight clock, and a follow-up that catches you if you only prepped one solution. The 40-minute slot can fit two problems so don't assume you're done after the first one.

Given an unsorted array, return the k-th largest element.
How would you handle this if elements are arriving one at a time and you always need to return the k-th largest so far?

“I went straight for the heap solution because it felt safer under pressure, and the interviewer immediately asked me to do it with quickselect instead.”

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Meta·Software Engineer·Onsite - System Design / Architecture

Jul 2026

Meta system design round for a software engineer role, focused entirely on building an online chess platform. Pretty scoped question but there's a lot of surface area once you start pulling threads on real-time state and reconnection logic.

Design an online chess platform that supports ranked and unranked matchmaking, real-time low-latency gameplay, server-enforced rules and timers, and persistent game history with reconnection support.

“I started with matchmaking and spent probably too long on the ELO ranking queue before realizing the real complexity was in the real-time move sync.”

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Meta·Data Scientist·Technical Phone Screen

Jul 2026

Meta DS interview focused entirely on a push notification product scenario. Three connected questions that built on each other, which I wasn't expecting. Felt like a product sense round disguised as analytics.

What metrics would you define to measure the quality of a push notification system?
How would you decide whether to ship the new notification experience based on experiment results?
If one metric goes up and another goes down after the experiment, how do you make sense of that and decide what to do?

“I started with click-through rate and immediately felt like that was too shallow.”

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Meta·Data Scientist·Technical Phone Screen

Jul 2026

Went through a technical screen for a DS role at Meta, heavy on ML systems and modeling fundamentals. The whole thing was basically one long case study about inheriting a broken churn model, which sounds contained until you realize how many sub-problems they're actually testing at once.

You inherit a churn prediction model where some features leak information from within the prediction window. Identify at least five concrete leakage sources in a logs-based feature set and rewrite each so it's computable at prediction time using a strict event-time cutoff.
Propose a rolling-origin cross-validation scheme for this model. Define train, validation, and test splits with no future leakage, and explain how you'd handle users entering or leaving the cohort and cold-start users.
Offline AUC is 0.79 and PR-AUC is 0.23. Online, targeting the top decile lifts conversion 1.5% but also raises cancellations by 0.3 percentage points. How do you define business KPIs and a cost-sensitive objective to tune the decision threshold? Include calibration and how you'd monitor calibration drift in production.
A standardized feature has a logistic regression coefficient of 0.40 and the model's baseline log-odds of churn is negative 1.50. Compute the odds ratio for a one standard deviation increase and the resulting change in churn probability from baseline. Then explain the limitations of interpreting coefficients this way when features are correlated.
Outline a production monitoring plan covering data quality, feature distribution shifts, PSI, label delay, and prediction drift. Include a retraining policy tied to both performance degradation and covariate shift triggers.

“This is where I spent most of my mental energy.”

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Meta·Data Scientist·Technical Phone Screen

Jul 2026

Meta DS interview focused entirely on trust and safety measurement. The whole thing was one long case about building a metrics framework and then designing an experiment for a harmful content detection system. Pretty intense if you haven't thought carefully about harm-weighted metrics before.

Propose metrics to measure both the severity and prevalence of inappropriate content on the platform. For each metric, explain your reasoning and walk through the tradeoffs.
Define the View Prevalence metric and justify why it's the right way to measure content exposure.
Design an A/B experiment to evaluate a new harmful content detection model. Cover your hypothesis, primary metric, guardrails, sample size and runtime estimates, and how you'd interpret the results.

“This is where I stumbled a bit.”

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Meta·Software Engineer·Technical Phone Screen

Jul 2026

Meta SWE coding round, one problem, pretty focused on the logic of filtering and arranging digits. Nothing fancy in terms of setup, just a straightforward algorithmic question that looks easy until you start thinking about edge cases.

Write a function that returns the smallest non-negative number that can be formed using only the odd digits from a given number. For example, given 12345, use only the digits 1, 3, and 5.

“My first instinct was to sort the odd digits in ascending order and concatenate them, which works, but I spent too long second-guessing whether leading zeros could appear or whether the result should be zero if there are no odd digits at all.”

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