OpenAI

OpenAI

Leading AI research laboratory developing state-of-the-art foundation models like GPT-4.

5 Rounds ~21 Days Very Hard
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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

Data Engineer • Coding • medium

Given a table of API requests (request_id, user_id, model_name, tokens_used, timestamp), write a SQL query to find the top 3 users by token usage for each model over the last 30 days, but only include users who have used at least two different models.

#Window Functions #CTEs #Aggregations
Practice
Data Engineer • Coding • hard

Design the database schema and write the SQL to track RLHF (Reinforcement Learning from Human Feedback) tasks. We have prompts, multiple model completions, and human rankings. How do you query for the inter-annotator agreement rate?

#Schema Design #Complex Queries #RLHF
Practice
Data Engineer • Coding • medium

Write a SQL query to calculate the 7-day rolling average of API requests per user, ensuring days with zero requests are factored into the average.

#Window Functions #CTEs #Date Generation
Practice
Data Engineer • Coding • hard

Given a table of user prompts, write a SQL query to find users who have submitted prompts in at least 3 different languages within any rolling 24-hour window.

#Self Joins #Window Functions #Time-Series
Practice
Data Engineer • Coding • hard

Write a SQL query to identify ChatGPT session boundaries. A new session starts if there is more than 30 minutes of inactivity between prompts from the same user.

#Gaps and Islands #Window Functions #LAG/LEAD
Practice
Data Engineer • Coding • medium

Given a table of model training runs (run_id, model_size, gpu_count, tokens_processed, duration_seconds), write a query to find the run with the highest throughput (tokens per second per GPU) for each model size.

#Ranking #Window Functions #Math
Practice
Data Engineer • Coding • medium

Write a SQL query to find the median token count per prompt for each day in the last month.

#Percentiles #Aggregation #Date Functions
Practice
Data Engineer • Technical • medium

Write a SQL query to find the top 1% of users by token consumption over the last 30 days, partitioned by pricing tier.

#Window Functions #Percentiles #Aggregations
Practice
Data Engineer • Technical • hard

Given a table of user interactions, write a query to calculate the session length for each user, where a session ends after 30 minutes of inactivity.

#Sessionization #Window Functions #CTEs
Practice
Data Engineer • Technical • hard

How would you optimize a slow-running SQL query that joins a massive `api_logs` table with a `users` table, where the `api_logs` table is highly skewed?

#Query Optimization #Data Skew #Joins
Practice
Data Engineer • Technical • medium

Write a query to find the daily retention rate of users who used a specific model (e.g., GPT-4) in their first week.

#Cohorts #Retention #Self Joins
Practice
Data Engineer • Technical • hard

Write a SQL query to identify 'bursty' API users—those who consume more than 10x their daily average tokens within a single hour.

#Advanced Aggregations #Window Functions #Time Series
Practice

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Senior Engineer

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