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."
Design Real-Time Fraud Detection with XGBoost Model
Real-Time Fraud Detection with XGBoost (Subscription Payments) Scenario You need to build and operate a real-time system that flags potentially fraudu...
Explain an End-to-End ML Project
In a first-round interview for a lead machine learning role, walk through your background and one machine learning project you led in detail. Your ans...
Compute Conv2D parameter counts
Parameter Count for a 2D Convolution Layer You are given a standard 2D convolution layer with: - Input channels: C_in - Output channels: C_out - Kerne...
Explain ROC-AUC vs PR-AUC tradeoffs
Question You trained a binary classifier that outputs predicted probabilities. Compare ROC-AUC and PR-AUC (the latter usually reported as Average Prec...
Explain Transformer Encoder and Decoder Behavior
Answer the following Transformer fundamentals questions in a machine learning interview: 1. What are the main differences between a Transformer encode...
Predict Bike Dock Demand
You are working on a docked bike-sharing system. Build a model that predicts how many bikes will be checked out from a specific dock in the next hour....
Determine When a Quadratic Has Finite Minimum
Consider the unconstrained real-valued optimization problem \[ \min_{x \in \mathbb{R}^n} f(x) = x^\top Qx + c^\top x, \] where \(Q \in \mathbb{R}^{n \...
When do you use mixed-effects models
You are modeling a user outcome (e.g., watch time or retention) across many countries and many users. Observations are nested (multiple days per user;...
Explain transformer architecture and variants
Technical Screen: Explain the Transformer Architecture Scope Provide a structured deep-dive into Transformers. Your explanation should cover theory, s...
How would you evaluate an AI feature?
You’re building an AI-powered feature (e.g., an AI assistant or AI-enhanced search). Interviewers ask: “How do you measure results and compare metrics...
Explain Vision Encoders and LLM Bottlenecks
Answer the following machine learning system fundamentals questions: 1. What is a vision encoder, and what role does it play in a computer vision or m...
Explain self-attention, LoRA, Adam vs SGD, ViT
Answer the following ML/Deep Learning interview questions: 1) Describe self-attention in Transformer models. What are the queries, keys, and values, a...
Explain modeling challenges and fixes
Model Development Challenges: Detection, Alternatives, Solution, Evidence Context: In a technical screen for a Machine Learning Engineer, you are aske...

Explain Transformers, attention, decoding, RL, and evaluation
Technical Screen: Transformers, Attention, Decoding, RLHF, Evaluation, and Optimization Context: Assume a modern decoder-only LLM unless stated otherw...
Design robber detection from surveillance video
You’re a Data Scientist on a team building a computer-vision system for public-safety monitoring. Problem Design an ML system that uses fixed surveill...
Implement and visualize in-place augmentations
Task: Build a Reproducible Augmentation Pipeline for Grayscale Digit Denoising Context You are training a denoising model on grayscale digit images (e...
How would you target promotions to grow consumers?
ML / Growth Scenario You own a system that sends promotion offers (e.g., "$10 off", "free delivery") to consumers to increase growth. Prompt Design an...
Explain train-test generalization gap
A model performs very well on the training set but much worse on a held-out test set. Explain why this can happen and how you would diagnose and fix i...
Build a leak-free sklearn churn pipeline
Take‑Home ML Task: Reproducible Subscription Classification Pipeline You are given a daily user-level dataset and must build a reproducible Python (sc...
Explain AUC, activations, ensembles, and imbalance
Machine Learning Metrics and Modeling Choices — Multi-part You are given model scores and binary labels for a small dataset and asked to compute ROC A...