Meta Interview Questions — Page 116

Meta·Data Scientist·Technical Phone Screen

May 2026

Meta DS interview with a pretty demanding structure: they want a full 60-second pitch, a deep-dive experimentation case end-to-end, and a 'why Meta' answer tied to a specific product surface. A lot to pack in, and the experimentation section especially goes way deeper than most companies.

Give a 60-second elevator pitch covering who you are, the scale you've worked at, and what you consider your core superpower as a data scientist.
Walk through an experimentation project end-to-end that had a measurable business impact. Cover problem framing, hypothesis, unit of randomization, primary and guardrail metrics, sample size and power calculations, experiment duration, any pre-registration or analysis plan, execution challenges, and final results with actual numbers.
After describing your experiment results, explain the causal story behind why the treatment worked, the trade-offs you considered, and what you'd do differently if you ran it again.
Why Meta? Map your motivations to a specific product area you'd want to join and explain how your skills are a fit for that team.

“Sounds easy until you actually time yourself.”

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Meta·Product Manager·Onsite - Product Sense / Strategy

May 2026

Meta PM interview with a product strategy question about whether Facebook should enter the 2D gaming space. Pretty open-ended, not a lot of scaffolding given.

Should Facebook launch a 2D gaming product?

“I went straight into market sizing and kind of forgot to anchor on why Facebook specifically.”

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Meta·Software Engineer·Technical Phone Screen

May 2026

Meta Research Scientist interview with a matrix manipulation problem that had a pretty interesting twist on how you think about complexity. The core coding was manageable but the follow-up on virtual indexing is where things got real.

You have an n x n matrix and a sequence of operations: swap two rows or columns, reverse a row or column, or rotate the whole matrix 90 degrees clockwise. Return the final matrix after all operations. Then discuss whether to simulate each operation literally or track transformations using index permutations and an orientation flag to get O(1) per operation.

“I started with the naive simulation and it felt fine until they asked about doing a thousand operations on a large matrix.”

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Meta·Software Engineer·Technical Phone Screen

May 2026

Meta SWE coding round, one algorithmic question about bus times and time arithmetic. Pretty straightforward on the surface but the edge cases tripped me up more than I expected.

Given a list of bus departure times in HH:MM format and a current time, find the most recent bus that has already departed. Return how many minutes ago it left, or -1 if none have passed yet.

“Felt fine parsing the times but I fumbled on the edge case where the current time is exactly on a departure time.”

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Meta·Data Scientist·Technical Phone Screen

May 2026

Meta DS interview with a SQL question focused on cross-country call analytics. Pretty straightforward technically but the double-join setup tripped me up for a moment.

Given a Users table and a Calls table, write a SQL query that returns, for each caller country and receiver country pair, the total number of calls and the average call duration over the last 30 days.

“The part that slowed me down was joining Users twice, once for the caller and once for the receiver.”

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Meta·Software Engineer·Technical Phone Screen

May 2026

Meta coding round for a software engineer role. The whole session was basically one meaty expression-evaluation problem with a bunch of follow-ups, and they really wanted to see how you handled operator precedence without just reaching for a library.

Implement a function that evaluates an arithmetic expression given as a string. The expression contains non-negative integers, the four basic operators, and spaces. Operator precedence applies (multiplication and division before addition and subtraction), and division should truncate toward zero. No parentheses. Can you do it in a single pass with minimal extra space?
Walk through your solution with the specific inputs '3/2', '14-3/2', and a string with a trailing operator. What does each produce and why?
Write unit tests for your evaluate function covering normal cases, edge cases, and invalid inputs.

“My first instinct was a two-pass approach: scan once for the high-precedence ops, then again for the rest.”

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Meta·Machine Learning Engineer·Onsite - System Design / Architecture

May 2026

System design round at Meta for an MLE role, focused entirely on building a weapon detection pipeline for ads. Dense question with a lot of moving parts, and I definitely underestimated how much they'd push on the policy and feedback loop side of things.

Design an end-to-end system to detect advertisements that contain weapons, covering data ingestion, feature extraction across image, text, and video modalities, labeling strategy, model architecture, inference modes, threshold tuning, and how you'd handle new weapon categories over time.

“This is a big question and I tried to walk through it linearly which was probably the wrong call.”

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Meta·Data Scientist·Technical Phone Screen

May 2026

Meta Data Scientist interview with a SQL-heavy question focused on marketplace analytics. Pretty straightforward setup but the specific framing around visibility rates and filtering by threshold tripped me up a bit.

Given a table of shop visibility records (shop ID, user ID, view date, and a boolean visible flag), write a SQL query to calculate each shop's daily visibility rate. Then identify shops whose average visibility rate across the past 7 days falls below 50%.

“I got the basic structure down pretty fast, CASE WHEN visible = true THEN 1 ELSE 0 END divided by count, grouped by shop and date.”

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Meta·Product Manager·Onsite - Product Sense / Strategy

May 2026

Meta PM interview with a single product design question around charity features. Pretty open-ended, which I wasn't fully prepared for.

Design a product for Facebook that enables or supports charitable giving.

“I went straight to listing features and the interviewer just kind of waited.”

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Meta·Software Engineer·Onsite - Coding / Algorithms

May 2026

Meta SWE interview with two fairly meaty algorithm problems back to back. The in-place merge had a nasty follow-up and the string grouping part was more subtle than it looked at first glance.

You have a sorted array A with some valid integers followed by sentinel (None) slots, and a separate sorted array B. You don't know how many valid elements are in A or how many sentinels there are. Implement an in-place merge into A in O(m+n) time using O(1) extra space. Cover edge cases like duplicates, negatives, and empty arrays.
As a follow-up to the in-place merge: can you merge by scanning forward from the beginning of both arrays instead of from the end? Why or why not, and give a concrete example showing what breaks.
Given an array of lowercase strings, group together strings that are equivalent under a uniform cyclic letter shift mod 26 and have the same length. For example 'abc' and 'bcd' are in the same group, as are 'az' and 'ba'. Define a canonical key and implement the grouping.
What is the time and space complexity of your string grouping solution, and how does it handle mixed-length strings or edge cases like empty strings?

“My first instinct was to scan from the front and I actually started coding that before the interviewer let me keep going for a bit and then asked me to think about what happens when you overwrite a value you haven't used yet.”

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