OpenAI
Leading AI research laboratory developing state-of-the-art foundation models like GPT-4.
5 Rounds
~21 Days
Very Hard
The Interview Loop
Recruiter Screen (30 min)
Standard fit check, behavioral questions, and resume overview.
Technical Loop (3-4 Rounds)
Deep dive into domain knowledge, coding, and system design.
Interview Question Bank
Software Engineer
•
System Design
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hard
Design the backend architecture for ChatGPT inference. How would you handle streaming responses, manage user context windows, and route requests to available GPU nodes?
#Distributed Systems
#Load Balancing
#WebSockets/SSE
#GPU Scheduling
Software Engineer
•
System Design
•
hard
Design a distributed key-value store optimized for storing and retrieving high-dimensional vector embeddings for a Retrieval-Augmented Generation (RAG) system.
#Vector Databases
#Sharding
#Replication
#Approximate Nearest Neighbor (ANN)
Software Engineer
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System Design
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hard
Design a system to handle distributed training checkpointing for a 100B+ parameter model. The system must ensure minimal downtime and data loss during frequent GPU node failures.
#Fault Tolerance
#Distributed Storage
#Network Bandwidth
#High Availability
Software Engineer
•
System Design
•
hard
Design a telemetry and monitoring system for OpenAI's API that can handle millions of events per second and detect anomalies in latency or token generation rates in real-time.
#Stream Processing
#Data Pipelines
#Anomaly Detection
#Time-Series Databases
Software Engineer
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System Design
•
hard
Design a vector database for semantic search and Retrieval-Augmented Generation (RAG).
#Databases
#Search
#Machine Learning
Software Engineer
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System Design
•
hard
Design a scalable Vector Database for storing and querying billions of embeddings with low latency.
#Databases
#Indexing
#Approximate Nearest Neighbor
#Distributed Systems
Software Engineer
•
System Design
•
hard
Design the backend architecture for ChatGPT, focusing specifically on handling streaming responses and maintaining conversation history.
#WebSockets
#Server-Sent Events
#Databases
#State Management
Software Engineer
•
System Design
•
hard
Design an infrastructure to reliably train a 100B+ parameter model across thousands of GPUs.
#Distributed Systems
#Machine Learning Infrastructure
#Fault Tolerance
Software Engineer
•
System Design
•
hard
Design a distributed key-value store optimized specifically for storing and retrieving LLM KV caches during inference.
#Distributed Systems
#Memory Management
#Latency Optimization
Software Engineer
•
System Design
•
hard
Design a rate-limiting system for the OpenAI API that handles millions of requests per second globally.
#Distributed Systems
#Redis
#Scalability
Software Engineer
•
System Design
•
hard
Design a load balancer specifically for LLM inference nodes, considering that generation times vary wildly based on output length.
#Load Balancing
#Queueing Theory
#LLM Inference
Software Engineer
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System Design
•
medium
Design a telemetry system to collect metrics and logs from millions of ChatGPT clients globally in real-time.
#Data Ingestion
#Streaming
#Analytics
Software Engineer
•
System Design
•
medium
Design a system to monitor and detect toxic or policy-violating prompts in real-time with minimal latency impact on the main API.
#Security
#Machine Learning
#Stream Processing
Software Engineer
•
System Design
•
medium
Design an asynchronous batch processing system for OpenAI's Batch API, where users submit millions of prompts to be processed within 24 hours.
#Batch Processing
#Queues
#Cost Optimization
Software Engineer
•
System Design
•
hard
Design a distributed file system for storing massive text datasets (petabytes) used for pre-training LLMs.
#Storage
#Distributed Systems
#High Throughput
Software Engineer
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System Design
•
hard
Design the backend infrastructure for ChatGPT, focusing specifically on low-latency streaming of tokens back to the client.
#WebSockets
#Server-Sent Events
#Microservices
#Latency Optimization
Software Engineer
•
System Design
•
hard
Design a rate-limiting system for the OpenAI API that handles millions of requests per second across different pricing tiers and token limits.
#Distributed Caching
#Redis
#Scalability
#Algorithms
Software Engineer
•
System Design
•
hard
Design a distributed data pipeline to ingest, clean, deduplicate, and tokenize petabytes of web text for LLM training.
#Big Data
#MapReduce
#Data Pipelines
#Storage
Software Engineer
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System Design
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medium
Design a caching layer for LLM responses to minimize redundant compute for identical or semantically similar prompts.
#Caching
#Semantic Search
#System Architecture
Software Engineer
•
System Design
•
hard
Design a system to monitor and detect model drift or harmful outputs in real-time across billions of API calls.
#Stream Processing
#Machine Learning
#Monitoring
Software Engineer
•
System Design
•
hard
Design an infrastructure to reliably serve large models (e.g., GPT-4) that require multiple GPU nodes for a single inference pass.
#Hardware Infrastructure
#Networking
#Model Serving
Software Engineer
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System Design
•
medium
Design a fine-tuning API where users can upload datasets and train custom models asynchronously.
#API Design
#Job Queues
#Storage
#Asynchronous Processing
Software Engineer
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System Design
•
hard
Design a highly available distributed file system optimized for heavy, sequential read workloads during model training.
#File Systems
#Distributed Storage
#Throughput Optimization
Software Engineer
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System Design
•
medium
Design a system to handle webhooks for asynchronous API completions, ensuring at-least-once delivery.
#Webhooks
#Message Queues
#Reliability
Software Engineer
•
System Design
•
hard
Design the backend architecture for ChatGPT to support real-time streaming responses.
#Server-Sent Events (SSE)
#WebSockets
#Microservices
#Load Balancing
Software Engineer
•
System Design
•
medium
Design a system to collect, store, and sample RLHF (Reinforcement Learning from Human Feedback) data at scale.
#Data Pipelines
#Databases
#Event Sourcing
Software Engineer
•
System Design
•
hard
Design a distributed, highly available rate-limiting system for the OpenAI API that handles millions of requests per second.
#Distributed Systems
#Redis
#Consistency
#API Gateways
Software Engineer
•
System Design
•
hard
Design a scalable vector database for storing and querying billions of text embeddings.
#Vector Search
#HNSW
#Sharding
#Distributed Storage
Software Engineer
•
System Design
•
hard
How would you design a system to load balance LLM inference requests across a heterogeneous GPU cluster (e.g., mixing A100s and H100s)?
#Load Balancing
#Hardware Awareness
#Scheduling
Software Engineer
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System Design
•
medium
Design a telemetry and alerting system to monitor GPU health and utilization across 10,000 nodes in real-time.
#Monitoring
#Time-Series Databases
#Data Aggregation
Software Engineer
•
System Design
•
medium
Design a semantic caching layer for the OpenAI API to save compute on identical or highly similar prompts.
#Caching
#Embeddings
#Cost Optimization
Software Engineer
•
System Design
•
hard
Design a system to handle web scraping at the scale of the entire internet for LLM training data collection.
#Distributed Crawling
#Deduplication
#Politeness Policies
Software Engineer
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System Design
•
hard
Design a multi-tenant architecture for fine-tuning models where enterprise users upload their own proprietary datasets.
#Multi-tenancy
#Security
#Data Isolation
#Job Queues
Software Engineer
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System Design
•
medium
Design a system to detect and block prompt injection attacks in real-time before they reach the core LLM.
#Security
#Stream Processing
#Classification
Difficulty Radar
Based on recent AI-sourced data.
Meet Your Interviewers
The "Standard" Interviewer
Senior EngineerFocuses on core competencies, system constraints, and clear communication.
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