ML System Design Interview Questions
Practice 277 real ML System Design interview questions for 2026. Covers companies like OpenAI, Meta, Amazon, Anthropic, and Google. Real questions from actual interviews with detailed solutions. This collection targets ML System Design interview questions and interview preparation for roles that must bridge modeling, data engineering, and production reliability. What’s distinctive: expect LLM- and RAG-focused problems (inference efficiency, retrieval, hallucination controls), feature-store and data-lineage designs, real-time versus batch inference trade-offs, GPU/TPU serving patterns (batching, KV-caches), monitoring for data and concept drift, and production CI/CD for models. Interviewers evaluate your ability to clarify requirements, choose constraints-aware architectures, reason about cost and latency, and specify metrics and guardrails for safety and observability. To prepare, practice drawing layered diagrams (ingestion, storage, feature pipeline, training, registry, serving, monitoring), rehearse trade-offs aloud, and build short writeups outlining metrics, retraining strategy, and rollback/alerting plans. Focus on clear assumptions, end-to-end reproducibility, and concrete operational details that show you can ship and maintain ML at scale.

"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"

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"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 RAG Retrieval for Data Assets
Design the retrieval component for an internal AI coding assistant. When a user asks a data-related question, the assistant should identify the most r...
Design a PDF-to-Markdown Inference API
Design an inference service that converts PDF files to Markdown. You can assume the following building blocks already exist: - A CPU-intensive functio...
Design a Text-to-Video Generation System
Design a Sora-like text-to-video generation platform. Users submit a text prompt, optional generation settings, and possibly optional conditioning med...
Design a Food Delivery Recommender
Design a recommendation system for a food delivery app similar to Uber Eats. When a user opens the home page, the system should recommend restaurants ...
Design GPU inference request batching
Design a system that serves online model-inference requests on GPUs. Requests arrive one at a time from clients, but GPU throughput is much better whe...
Build a Candidate Search System
Build an end-to-end candidate search system for recruiting. Input Each search request contains a job posting with: - Job title - Job description - Har...
Design Uber Eats Restaurant Recommendations
Design a restaurant recommendation system for the Uber Eats home page. A user opens the Uber Eats app and should see a ranked feed of restaurants avai...

Design an LLM API pipeline
You need to build a small application feature that calls a hosted large language model API to solve a user task. In the interview, you are expected to...
Design an Automated Ticket Investigation Agent
Design an AI-enabled agentic system that automatically investigates support or engineering tickets. The system should: - Read an incoming ticket and u...
Design GenAI Fine-Tuning and Agent Tradeoffs
You are interviewing for a software engineering role involving generative AI infrastructure and quantitative applications. The interviewer wants to un...
Design Model Weight Distribution
Design a system for distributing large machine learning model weight files to a fleet of inference workers. Context: - Model weights may be tens to hu...
Design a Game Recommendation System
Design an end-to-end machine learning recommendation system for a large online gaming platform. The platform has many users and many games. When a use...
Design a high-concurrency LLM inference service
You are designing an LLM inference platform that serves interactive user requests (chat/completions) on GPUs. Goals - Support high concurrency with pr...
Prevent Private Code Leakage in Coding Agents
Meta trains or fine-tunes coding agents using private source-code repositories. These agents may later be used to answer coding questions, generate co...
How do you handle an LLM agents interview?
You have an interview on your agenda titled “Agents Interview.” Explain how you would approach this interview if it is about designing and evaluating ...
Design Chatbot Personalization Memory
Design a text-only personalization and memory system for an AI chatbot. The chatbot should use a user's previous conversations, preferences, and feedb...

Design pipeline using classification and embedding services
You are given two black-box ML services: 1. Classification Service - Input: One or more text documents. - Output: A label for each document (e.g...
Design a Drop-off Spot Selector
Design an ML-driven decision system for an autonomous ride-hailing vehicle that must choose where to stop when a passenger is arriving at the destinat...
Design a prompt playground
Design a prompt playground for working with large language models. Users should be able to write prompts, run them against one or more models, compare...
Design a Product Search System
Design a product search system for a large e-commerce marketplace. Users enter free-text queries such as wireless headphones, apply filters such as pr...