Prepare for the interview.
159 interview-style questions for forward deployed and AI engineering roles. 22 come with the full scoring rubric, and 23 are linked to a named company by a candidate report or prep guide.
Question bank
Showing all of 159 questions
- 1An agent has access to several hundred tools. Their definitions consume most of the context window before the user’s request is even read. Design a fix. (opens in a new tab)
- 2What is an agent harness, and what specifically does it add over a well-engineered single prompt for a long-running task? (opens in a new tab)
- 3An integration protocol currently requires a handshake to establish a session, after which every subsequent message must reach the same server instance. Explain the scaling problems and how you would redesign it. (opens in a new tab)
- 4You are designing quota enforcement for a paid LLM API. A single shared account can consume 140 hours of GPU time over a week while never looking abnormal in any one-minute window. Design the limiting scheme and defend the number of limits you chose. (opens in a new tab)
- 5How would you design Netflix’s search bar to return results for the query ‘that show with the guy from Breaking Bad’ without any exact keyword matches? (opens in a new tab)
- 6What are the key steps to design a system that allows Gemini to browse the web in real time and provide accurate answers without hallucinating outdated facts? (opens in a new tab)
- 7What are the key steps to design an AI moderation system for removing harmful content from 500 million posts per day in under 1 second? (opens in a new tab)
- 8How do you design a voice AI that retains user preferences and conversations while ensuring data can be deleted in under 1 second upon user request? (opens in a new tab)
- 9How do you design an on-device LLM that works fully offline on an iPhone, considering model size, memory, and privacy? (opens in a new tab)
- 10What are the key steps to design a multi-tenant LLM platform ensuring data isolation for 500 enterprise clients? (opens in a new tab)
- 11A stakeholder believes the model ‘connects to the internet’ to answer questions with fresh information. Correct the picture and describe the actual data flow. (opens in a new tab)
- 12A multi-tenant RAG assistant is returning documents from other customers’ accounts. Diagnose the design flaw and tell me how you would fix it. (opens in a new tab)
- 13How do you handle stale context in a RAG pipeline where the knowledge base updates every 5 minutes? (opens in a new tab)
- 14What are the key steps to design an embedding pipeline that maintains accuracy in vector search when scaling a product catalog from 1M to 1B items? (opens in a new tab)
- 15How would you design a GenAI system that rewrites a user’s resume based on a job description with a latency of under 2 seconds? (opens in a new tab)
- 16How would you design a prompt caching system for 1 billion daily LLM API calls while optimizing for cost and latency? (opens in a new tab)
- 17Walk me through the request path for a conversational AI product serving hundreds of millions of users, and tell me which parts genuinely need exotic infrastructure. (opens in a new tab)
- 18How can you redesign Alexa using an LLM backend to ensure responses are conversational, fast, and accurate while the user is mid-sentence? (opens in a new tab)
- 19How would you design an AI shopping assistant to handle vague emotional queries such as ‘something my mom would love for her birthday under ₹2000’? (opens in a new tab)
- 20What happens when you type a question into ChatGPT? Explain the system behind it. (opens in a new tab)
- 21How would you design a system using GenAI to clean up a codebase of 2 million lines across 14 microservices, focusing on what to modify and what to avoid? (opens in a new tab)
- 22What are the key steps to design a pipeline for auto-generating personalized trailers for Netflix using GenAI? (opens in a new tab)
- 23What are the main considerations for designing a pipeline to enable an LLM to write episode recaps, predict plot holes, and flag continuity errors for Netflix? (opens in a new tab)
- 24How can Instagram’s AI build a perfect interest profile for a user who never posts, comments, or likes? (opens in a new tab)
- 25How can you design a GenAI system for real-time misinformation detection on WhatsApp while ensuring end-to-end encryption and user privacy? (opens in a new tab)
- 26How do you design a GenAI rebalancing system for Uber that handles multiple driver cancellations in under 10 seconds? (opens in a new tab)
- 27How do you design a system for a 99.9% accurate LLM to catch the 0.1% failures before users encounter them? (opens in a new tab)
- 28How does Netflix decide which thumbnail to show to different users for the same show? (opens in a new tab)
- 29What are the key design steps for making WhatsApp Pay accessible for a 65-year-old in a village with 2G internet and zero digital literacy? (opens in a new tab)
- 30What are the key steps needed to design an LLM-powered ad generator that creates unique ad copy for 10 million products while avoiding misleading claims? (opens in a new tab)
- 31What are the key steps to building a GenAI system that rewrites a user’s resume in real time under 2 seconds? (opens in a new tab)
- 32How should a voice AI system like Alexa handle potentially dangerous requests made by children, and what are the key design principles to ensure child safety? (opens in a new tab)
- 33What are the key steps in designing a real-time detection and rollback system to contain a jailbreak for an AI model like GPT-5? (opens in a new tab)
- 34How do you design context windows for an AI model to ensure it never loses track of the conversation? (opens in a new tab)
- 35A company already exposes REST APIs for everything. Make the case for adding a standard tool-integration protocol on top, and then argue the other side. (opens in a new tab)
- 36How can Swiggy design a system to predict customer order surges based on weather changes in Bangalore? (opens in a new tab)
- 37How do you design a multilingual semantic search engine that accurately handles mixed-language queries like ‘blue wali dress under 500’ despite having zero exact keyword matches? (opens in a new tab)
- 38What is RAG (Retrieval-Augmented Generation) in the context of AI chatbots, and how does it improve the accuracy of responses? (opens in a new tab)
- 39What is the process for designing a semantic search engine that understands meaning? (opens in a new tab)
- 40What are the key steps to designing a GenAI content recommendation engine that explains its recommendations? (opens in a new tab)
- 41What are the key steps to designing an AI search engine that cites sources and ranks answers by confidence rather than just relevance? (opens in a new tab)
- 42What are the steps to design a Generative AI system that determines why a user quits watching a show after 10 minutes and how it can improve future recommendations? (opens in a new tab)
- 43A customer says their AI deployment ‘can reason about the problem but never actually does anything’. They are calling a model API directly. Explain what is missing architecturally and what you would build. (opens in a new tab)
- 44How would you approach designing a system to dub a show into 40 languages using GenAI while preserving lip-sync, tone, and emotional delivery? (opens in a new tab)
- 45How would you design a parallel processing pipeline for YouTube’s GenAI that auto-generates captions, chapters, a thumbnail, and a description within 60 seconds after a creator uploads a video? (opens in a new tab)
- 46What design steps are necessary to ensure VPC isolation for fine-tuning a language model on AWS, preventing any data from leaving the VPC? (opens in a new tab)
- 47Build an agent that reads a CSV of customer data and generates personalized email campaigns, including quality evaluation metrics. (opens in a new tab)
- 48Build an agent that reads code, understands its purpose, and suggests improvements. (opens in a new tab)
- 49Create a system where multiple agents collaborate to produce a research report with citations. (opens in a new tab)
- 50Describe how you would architect an AI agent system: the agent loop, tool interfaces, memory design, orchestration, and safety. (opens in a new tab)
- 51Design a multi-step agentic workflow for meeting scheduling, code review, or email campaigns. (opens in a new tab)
- 52Design an agent that analyzes customer support tickets, drafts responses automatically, and escalates complex issues. (opens in a new tab)
- 53Design an agent that recovers from its own failures. (opens in a new tab)
- 54Design the memory layer for an agentic application. (opens in a new tab)
- 55How do you prevent an agent’s memory from going stale? (opens in a new tab)
- 56Implement a code review agent that analyzes Python files and gives actionable feedback, with accuracy evaluation. (opens in a new tab)
- 57When is agentic RAG worth the complexity over plain RAG? (opens in a new tab)
- 58Your AI agent keeps calling the wrong tool. How do you fix it? (opens in a new tab)
- 59Design a large language model-powered chat system. (opens in a new tab)
- 60Design an AI chatbot (a ChatGPT or Claude-style chat service). (opens in a new tab)
- 61Design ChatGPT. (opens in a new tab)
- 62Design our Claude chat service. (opens in a new tab)
- 63How would you design the UX for an AI assistant that is often slow? (opens in a new tab)
- 64Design a document classifier that routes resumes to the right teams. (opens in a new tab)
- 65Design an AI coding co-pilot like GitHub Copilot. (opens in a new tab)
- 66Design a system that lets doctors automatically send billing information to insurers based on patient notes. (opens in a new tab)
- 67Design the OpenAI API itself: key management, authentication, per-key rate limiting, usage metering, billing, and tenant isolation. (opens in a new tab)
- 68Design usage quotas and billing for an AI API, including per-token metering and accurate billing under retries. (opens in a new tab)
- 69How would you scale an AI search assistant for a website with 10M+ articles? (opens in a new tab)
- 70Scale an AI chat feature to 1M daily users and discuss the trade-offs. (opens in a new tab)
- 71Your AI traffic grows 100x. What breaks first and what do you change? (opens in a new tab)
- 72Your app gets 1M LLM queries a day. How do you optimize cost? (opens in a new tab)
- 73Design a generative AI document-processing pipeline for emails, PDFs, and images to automate claims processing. (opens in a new tab)
- 74Design a scalable data pipeline for machine learning applications, from ingestion through processing to a feature store. (opens in a new tab)
- 75Design a unified query engine across dispersed data sources: email, calendar, documents, and chat. (opens in a new tab)
- 76How do you ingest and process structured, unstructured, and event data for an AI system? (opens in a new tab)
- 77How do you ingest and process structured, unstructured, and event data in one pipeline? (opens in a new tab)
- 78How would you handle real-time versus batch processing for data updates in an AI product? (opens in a new tab)
- 79How would you handle real-time versus batch processing for data updates, and when is each preferred? (opens in a new tab)
- 80How would you design a model that solves math problems? Walk through data collection, SFT, post-training, and evaluation. (opens in a new tab)
- 81Which offline and online metrics would you use for a search ranking system, and what edge cases break the online ones? (opens in a new tab)
- 82Your eval scores are high but users still complain. What is wrong with your evaluation? (opens in a new tab)
- 83Can smaller models improve an AI system? Where would you route to them? (opens in a new tab)
- 84Design a fraud detection system. (opens in a new tab)
- 85Design a real-time fraud detection system. (opens in a new tab)
- 86Design a system to process 10K user uploads a month (bank payslips, IDs, references). (opens in a new tab)
- 87Design a system to process 10k user uploads a month. How do you extract data, detect inconsistencies, reject invalid files, and handle LLM provider downtime? (opens in a new tab)
- 88Design an AI-powered candidate sourcing system. (opens in a new tab)
- 89How would you design a feedback loop that improves an AI writing tool over time? (opens in a new tab)
- 90How would you design an LLM-powered enterprise search system? (opens in a new tab)
- 91How would you surface model limitations or errors to users without breaking trust? (opens in a new tab)
- 92Propose an indexing approach for a product catalogue yourself, and explain how new products get added to the index. (opens in a new tab)
- 93You are building an AI tool that generates legal contracts from a prompt. What is your approach? (opens in a new tab)
- 94Design a content and policy violation detection system. (opens in a new tab)
- 95Design a real-time chatbot API for AI-driven conversations, covering context state, latency targets, safety filters, and rate limiting. (opens in a new tab)
- 96How would you build a chatbot for a bank that must not hallucinate? (opens in a new tab)
- 97How would you design a language model that minimizes harmful outputs while staying useful and expressive? (opens in a new tab)
- 98Design ChatGPT’s cross-conversation memory feature. (opens in a new tab)
- 99Design a small language model that runs on a phone while making sure it stays polite. (opens in a new tab)
- 100Design a voice assistant for hospital staff. Which challenges do you solve first? (opens in a new tab)
- 101Design a credit tracking service for user token balances. (opens in a new tab)
- 102How do you enforce multi-tenant isolation in an AI system? (opens in a new tab)
- 103How would you standardize LLM access across multiple teams in one company? (opens in a new tab)
- 104Design a legal contract generation system with compliance requirements. (opens in a new tab)
- 105Create a document Q&A system with citation tracking that handles multi-hop questions. (opens in a new tab)
- 106Design a conversational recommender system combining chat, retrieval, and a product database. (opens in a new tab)
- 107Design a document Q&A assistant backed by a RAG pipeline. (opens in a new tab)
- 108Design a Q&A assistant over internal company documents where accuracy is critical. Where do you begin? (opens in a new tab)
- 109Design a RAG chatbot for a financial institution that answers only summary-of-services questions. It must give no financial advice, capture no PII, and survive jailbreak attempts. Where do the guardrails, human-in-the-loop, and audit trail go? (opens in a new tab)
- 110Design a RAG system for over 10 million documents. (opens in a new tab)
- 111How do you handle conflicting documents in a RAG system? (opens in a new tab)
- 112How do you handle prompt injection that arrives through retrieved documents? (opens in a new tab)
- 113Pitch an end-to-end RAG service in 15 minutes: ingestion, indexing, retrieval, generation, evals, tracing, guardrails, cost and latency trade-offs, and a rollback story. (opens in a new tab)
- 114Scale a RAG system from 10 thousand documents to 100 million. (opens in a new tab)
- 115Trade off recall against precision in a RAG pipeline. Which do you favour and when? (opens in a new tab)
- 116Why is semantic search alone not enough for production RAG? (opens in a new tab)
- 117Your RAG chatbot gives fluent but wrong answers. Diagnose it. (opens in a new tab)
- 118Design a large e-commerce search engine with product ranking from scratch. (opens in a new tab)
- 119Design a Perplexity-style real-time LLM-powered search engine. (opens in a new tab)
- 120Design a recommendation system. (opens in a new tab)
- 121Design a high-QPS LLM inference service. (opens in a new tab)
- 122Design a hospital voice assistant that handles background noise, patient privacy, latency, and domain vocabulary. (opens in a new tab)
- 123Design a large-scale AI model deployment system covering model serving, GPU scaling, model versioning, and result caching. (opens in a new tab)
- 124Design a large-scale AI model deployment system: how would you serve a GPT-4-class model to millions of concurrent users? (opens in a new tab)
- 125Design a scalable image-generation pipeline serving millions of users. (opens in a new tab)
- 126Design token streaming for a chat endpoint. Compare SSE and WebSockets, explain backpressure, and handle mid-stream failures. (opens in a new tab)
- 127Here is a junior developer’s design for an inference batching system. Review it and explain what you would change. (opens in a new tab)
- 128How do you measure LLM latency in a chat app, and which percentile matters? (opens in a new tab)
- 129What is a KV cache, and how does it help LLM inference? (opens in a new tab)
- 130Design a distributed job queue for 100k+ GPU training jobs with preemption and checkpointing. (opens in a new tab)
- 131Design a distributed job queue for GPU training jobs, including priority and preemption. (opens in a new tab)
- 132Design a distributed training system for deep learning models, covering data and model parallelism, scheduling, weight syncing, and failure handling. (opens in a new tab)
- 133How would you design a scalable system for training an LLM under both compute and data constraints? (opens in a new tab)
- 134Why can LLM training be parallelized, and where does that break down? (opens in a new tab)
- 135A sharded database routes by user_id modulo shard count. The team wants to add a shard. Explain what will happen and design something better. (opens in a new tab)
- 136Design notification delivery to 50 million mobile devices. The current design has each device polling the backend every 20 seconds. Walk me through what you would change. (opens in a new tab)
- 137An API endpoint sends an email inline and times out when the mail provider is slow. Design the background-processing system, and be specific about what can still go wrong. (opens in a new tab)
- 138Design an API rate limiter for a multi-node service. A colleague proposes counting requests per clock minute. Show them why that fails and what you would build. (opens in a new tab)
- 139Add a column to a 300 million row table that is serving traffic 24/7, with zero downtime. Walk me through the exact sequence. (opens in a new tab)
- 140A six-pod food-delivery backend starts cascading pod restarts whenever its Postgres instance gets slow, even though the application code is healthy. The team’s /health endpoint runs a database query and is wired to the liveness probe. Walk me through what is happening and how you would fix it. (opens in a new tab)
- 141Twenty product teams each maintain their own CI/CD pipelines, databases, and monitoring. Design the fix, and tell me how you would know whether it worked. (opens in a new tab)
- 142A company’s public marketing site and its payments service run in the same Kubernetes cluster. The marketing site is compromised. Explain the exposure and design the containment. (opens in a new tab)
- 143A team is hitting a database bottleneck and has proposed sharding. How would you decide whether sharding is the right move, and what would you do instead if it is not? (opens in a new tab)
- 144A team provisions cloud resources with Terraform in CI. Someone changes a setting by hand in the console and nothing notices for three weeks. Design a system where that cannot happen, and tell me what you give up. (opens in a new tab)
- 145Adding a nullable column to a large Postgres table takes production down. The team assumes Postgres is rewriting every row. They are wrong. What is actually happening, and how do you make migrations safe? (opens in a new tab)
- 146Checkout is failing because Postgres has hit its 200-connection limit. The on-call engineer wants to raise the limit. Talk me through the right response. (opens in a new tab)
- 147Design the driver-matching service for a ride-hailing app. Tens of thousands of drivers per city each report their location every four seconds, and a rider request must be matched in under a second. Walk me through your design. (opens in a new tab)
- 148Explain the CAP theorem and then use it to make an actual design decision for a system you choose. (opens in a new tab)
- 149Forty production nodes, continuous traffic, and a Kubernetes version approaching end of life. Plan the upgrade with no user-visible downtime. (opens in a new tab)
- 150Plan a migration of a CI fleet and developer laptops from Docker to Podman. An engineer has proposed aliasing docker to podman and calling it done. Where does that break? (opens in a new tab)
- 151Users in Sydney are waiting on a write round trip to a primary database in Virginia, and a Virginia outage blocks writes globally. Design a fix and tell me what new problem you have created. (opens in a new tab)
- 152Your primary database is down and a replica is available for promotion. Give me the order of operations and justify each step. (opens in a new tab)
- 153A Kubernetes node fails. Stateless pods reschedule fine, but the StatefulSet pods stay in Terminating indefinitely. Explain why, and give me the safe recovery procedure. (opens in a new tab)
- 154A scan of over 300,000 public container images found private keys in more than 28,000 of them. Explain how keys end up in images and how you would prevent it. (opens in a new tab)
- 155A team says their Kubernetes control plane is highly available because the API server runs three replicas. What is your assessment? (opens in a new tab)
- 156You are draining a Kubernetes node. Eleven pods evict cleanly, the twelfth is refused by the eviction API and the drain hangs. What is happening, and what do you do? (opens in a new tab)
- 157A customer tells you their data is safe because the database is replicated across three availability zones. What is your response, and what would you build? (opens in a new tab)
- 158Compare a daemon-based container runtime with a daemonless one, and tell me where you would deploy each. (opens in a new tab)
- 159When would you deploy a workload in a virtual machine rather than a container? Make the case both ways. (opens in a new tab)
No questions match. Try another topic or a shorter search.
Each question opens on its own page, with the full rubric or a reference sketch where one exists. 71 come from FDEBench’s own bank; the rest from candidate reports, prep guides and videos (IGotAnOffer, the AI Engineering Field Guide, Keerti Purswani, DesignGurus and others). FDEBench is not affiliated with any company named.
What the loops ask
From one student’s eight AI interview loops
What they ask most
Customers and stakeholders
How you handle people who aren’t technical, and whether you’ve worked with outside customers.
The technical rounds
They vary a lot
Debugging real code and logs, or building a feature from scratch, some with AI and some without.
The final round
A pitch, under questions
A deck and a proof of concept built on their product, presented like a customer or investor pitch.
If you come from engineering, expect them to test the customer side hardest.
A bootcamp student, October 2026, shared with permission and paraphrased.
One framework for each round
A framework is how a 45-minute room hears judgment
Customer and stakeholder questions
STAR: situation, task, action, result
“Here’s what was going on, what I had to do, what I did, and what changed.” End on a number.
Debugging and “fix this”
Reproduce it, read the logs, change one thing
“I can make it fail every time. The logs point here. I changed one thing. Next I’d check this.”
AI system design
The seven moves, below
“Before I draw anything: what number would tell us it works?”
The pitch and the proof of concept
The five-line brief
“What it does, what it costs per run, what could go wrong, who signs off, and the one number we’d track.”
The design round, in seven moves
43 of the 45 minutes, and what you say at each
Contract 5 minminutes 0–5
“Before I design anything: what does good look like? How fast, how accurate?”
Baseline 2 minminutes 5–7
“Simplest version: one prompt, one model call. Here’s where it falls short.”
Flow 12 minminutes 7–19
“Let me walk one request from the moment it comes in to the reply.”
Eval 8 minminutes 19–2716.5% of points
“Here’s how I’d know it works before a single user complains.”
Failure 8 minminutes 27–3531% of points
“Here’s what breaks first, and what the user sees when it does.”
Numbers 5 minminutes 35–40
“Let me do the cost out loud: tokens per call, times calls, times price.”
Iterate 3 minminutes 40–43
“In week one I’d ship this small piece, measure it, then add the rest.”
47.5% of the points sit in eval and failure.
In FDEBench’s first 10 rubrics (63 criteria worth 1,000 points), failure modes carry 31% of the points and evaluation 16.5%.
Show the seven moves as a table
| Move | Minutes | Starts at | Share of points |
|---|---|---|---|
| Contract | 5 | 0 | – |
| Baseline | 2 | 5 | – |
| Flow | 12 | 7 | – |
| Eval | 8 | 19 | 16.5% |
| Failure | 8 | 27 | 31% |
| Numbers | 5 | 35 | – |
| Iterate | 3 | 40 | – |
A worked answer
Illustrative numbers
The question“Your AI agent keeps calling the wrong tool. How do you fix it?”
- ContractThe right tool on the first try for 95 of 100 real requests.
- BaselineRead 50 traces, the log of each request, and count which tools get confused.
- FlowRequest → tool descriptions → the choice → its arguments.
- Eval100 logged requests labelled with the right tool, scored before and after every change.
- FailureTwo tools with overlapping descriptions, too many tools, a vague request: ask a question back.
- NumbersFewer tools means a shorter prompt and a lower bill.
- IterateRewrite the descriptions first, then cut or group tools, then add routing: a first step that picks the group.
Start with the cheapest fix you can measure.
Guides for each round
All guides- The forward deployed engineer interview, round by roundForward deployed engineer interview prep: what each FDE round tests, a framework for each one, and practice questions with full scoring rubrics.Read
- RAG interview questions: what FDE loops ask and how answers are scoredRAG interview questions from FDE and AI engineering loops: what to ask first, hybrid vs agentic retrieval, numbers to estimate and mistakes that cost points.Read
- AI agent interview questions: how agent design rounds are scoredAI agent interview questions for FDE and AI engineering loops: one agent or several, where guardrails go, memory, the numbers to estimate and what loses points.Read
- LLM cost and latency interview questions: caching, routing and the math to say out loudLLM cost and latency interview questions for FDE and AI engineers: caching layers, model routing, the token math to do out loud and mistakes that cost points.Read
- AI evaluation interview questions: evals, metrics and production readinessAI evaluation interview questions for FDE and AI engineers: what to define first, which eval methods to name, the sample-size math and the go/no-go gates.Read
- The customer round: scoping, demos and handoffThe FDE customer interview round explained: how to scope a vague ask, handle a stakeholder role-play, present a demo and plan the handoff.Read
Questions people ask
What do forward deployed engineer interviews ask?
Across one student’s eight AI interview loops: customer and stakeholder questions came up most, the technical rounds varied (debugging real code and logs, or building a feature, with or without AI), and the final round was a pitch: a deck and a proof of concept built on the company’s product. What the loops ask.
How do I prepare for an FDE interview?
Use one framework per round. STAR for customer and stakeholder questions, “reproduce it, read the logs, change one thing” for debugging, the seven moves for AI system design, and a five-line brief for the pitch. Then practice out loud on real questions and score yourself against a rubric. The interview, round by round.
What is in a full rubric?
22 questions have one. It lists what a strong candidate asks before designing, criteria weighted to 100 points with what earns full credit and the feedback if you miss it, and the red flags that would end the interview.
Where do the questions come from?
71 come from FDEBench’s own bank. The rest come from candidate reports, Reddit, prep guides, field guides, newsletters and YouTube. 23 are linked to a named company, and each says whether a candidate reported it or a guide names it.
How should I spend a 45-minute AI system design round?
In seven moves: agree what good looks like (5 minutes), the simplest baseline (2), the request flow (12), how you would evaluate it (8), what breaks first (8), the cost out loud (5), and what you would ship in week one (3). In FDEBench’s first 10 rubrics, failure modes and evaluation carry 47.5% of the points.
Want feedback from a live cohort?
The bootcamp includes a module on landing the role and passing the interview. The next cohort starts 14 Nov.