Machine Learning Interview Questions
Practice 639 real Machine Learning interview questions for 2026 — Machine Learning interview questions drawn from Amazon, Meta, Google, TikTok, and Capital One, with real questions from actual interviews and detailed solutions. This collection is built for interview preparation focused on production-ready ML: expect questions that test modeling and mathematics, coding in Python, ML system design, MLOps and deployment, and modern GenAI topics such as transformer fundamentals, embeddings, and retrieval-augmented generation. Companies emphasize reliability, data quality, and end-to-end ownership as much as algorithmic chops. What’s distinctive: interviews now blend theory, coding, and system thinking — you’ll be evaluated on algorithmic intuition, experiment design and metrics, feature and data engineering, model monitoring and drift detection, and cost/reliability tradeoffs for serving models at scale. To prepare, strengthen fundamentals (linear models, trees, probabilistic reasoning), implement end-to-end projects, rehearse ML system-design case studies, and run mock interviews that combine coding, math, and production scenarios.

"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"

"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"

"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."

"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."

"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."

"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."

"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."

"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."

"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."

"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."

"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."

"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."

"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."

"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Improve low R² without p‑hacking
Predicting Contribution per Order with Low R² Context You are modeling contribution per order (a continuous per-order outcome such as margin or profit...
Design a battery-life predictor and cold-start strategy
Smartphone Time-to-Empty (TTE) Prediction — Baseline, Features, Cold Start, Evaluation, and Monitoring Context You are building a per-device predictor...
Design real-time payments fraud model under constraints
Real-Time ML Policy Design: Prevent Unauthorized Purchases by Minors Context: You need to reduce unauthorized purchases by minors using their parents'...
Explain SHAP vs VIF under collinearity
High Collinearity in Binary Classification: VIF, SHAP, and Interpretation Strategy You are modeling a binary outcome Y. Two numeric features A and B a...
Implement Multi-Head Self-Attention
Implement a multi-head self-attention module in PyTorch without using torch.nn.MultiheadAttention. Requirements: - Input tensor shape: (batch_size, se...
Explain PPO and Transformer basics
PPO, Bellman Equations, On-/Off-Policy Learning, and Transformer Basics Context: You are interviewing for a machine learning role with emphasis on rei...
Explain variance reduction in random forests
Consider a random forest (or bagged ensemble) that predicts at a fixed input \(x\) by averaging \(B\) tree predictions: \[ \hat f_B(x) = \frac{1}{B}\s...
Design a house-price prediction model
Problem You are asked to build a model to predict house sale prices for a city of your choice. Data (assume typical real-estate fields) You have a his...
Explain annotation agreement and LLM vs human judges
Annotation Agreement and LLM-vs-Human Judges Context You are on a model-evaluation team. Datasets are labeled, and model outputs are scored, by humans...
Fit logistic regression and return top features
You are given: - X: a 2D numeric array where each row is a feature and each column is an observation (shape: n_features x n_samples). - feature_names:...
Which clustering algorithm would you use and why
Question You need to cluster users for a social product (e.g. Meta) to discover meaningful groups such as communities, interest groups, or usage segme...
Implement AUC-ROC, softmax, and logistic regression
You are asked to implement a few core ML building blocks from scratch (no ML libraries such as scikit-learn). You may use basic numeric operations and...
Design a robust fraud detection system
Real-Time Card Fraud Detector — End-to-End Design Context - Fraud base rate ≈ 0.2% (severe class imbalance) - Labels arrive with a 14-day delay (e.g.,...
Design a leak-free time-split model
Predict 30-Day Purchase Probability at a Snapshot (Technical Screen) Assume you have user, event, and order data with two timestamps per row: - event_...
Model flight delays with EDA and explanation
Predicting 15+ Minute Arrival Delays at Scheduled-Departure Time You are building a binary classifier that predicts whether a domestic flight will arr...
Build a Bayes classifier for reviewer types
Bayesian Reviewer-Type Inference Setup There are two reviewer types: - Lazy (prior probability 0.20): always gives a "Good" review. - Careful (prior p...
Implement robust k-means from scratch
Implement K-Means Clustering From Scratch (Production-Ready) Context You are asked to implement K-Means clustering from scratch for a machine learning...
Explain Train-Test Performance Gap
A supervised model for a TikTok-like product problem performs very well on the training set but much worse on a held-out test set. How would you diagn...
List hyperparameter tuning methods
Describe common methods for hyperparameter tuning in machine learning. For each method, explain: - How it works conceptually. - Its advantages and dis...
Identify Risks and Improve Imputation Class Implementations
Scenario You are reviewing three custom Python imputation classes intended for use in a scikit-learn workflow. Each class fills missing values column-...