AI Engineer • Behavioral • hard

Tell me about an AI project where you had to balance innovation with reliability.

#Reliability #Innovation

Practice

AI Engineer • Behavioral • hard

Describe an AI product you built from scratch. What were the key technical decisions?

#Product Development

Practice

AI Engineer • Behavioral • hard

Tell me about a time an AI system you built produced unexpected or harmful outputs.

#Responsibility #Ethics

Practice

AI Engineer • Behavioral • easy

How do you stay current with the fast-moving AI/ML research landscape?

#Research #Continuous Learning

Practice

AI Engineer • Behavioral • medium

Describe a time you had to choose between using an AI model and a simpler rule-based system.

#Tradeoffs #Pragmatism

Practice

AI Engineer • Behavioral • medium

Tell me about a time you optimized an LLM application for cost or latency.

#Cost #Latency

Practice

AI Engineer • Behavioral • medium

How do you handle stakeholder uncertainty around AI capabilities and limitations?

#Stakeholders #Expectations

Practice

AI Engineer • Behavioral • hard

Describe a situation where you had to debug a hard-to-reproduce AI model failure.

#Problem Solving

Practice

AI Engineer • Coding • medium

Write a retry mechanism with exponential backoff for LLM API calls.

#Reliability #APIs

Practice

AI Engineer • Coding • hard

Implement a simple RAG pipeline using Python, LangChain, and FAISS.

#RAG #Python

Practice

AI Engineer • Coding • medium

Write a Python class to manage conversation history for a multi-turn chatbot.

#Chatbot #Memory

Practice

AI Engineer • Coding • hard

Implement a semantic chunking strategy for long documents.

#Chunking #Embeddings

Practice

AI Engineer • System Design • hard

How would you architect an AI platform that supports 1000 concurrent LLM requests?

#Scaling #LLM Serving

Practice

AI Engineer • System Design • hard

Design a real-time AI safety filter for user-generated content.

#Content Moderation #Real-Time

Practice

AI Engineer • System Design • hard

How would you build a multi-modal AI system that processes both text and images?

#Multi-Modal #Vision

Practice

AI Engineer • System Design • hard

Design an AI code review system that integrates with GitHub PRs.

#Code Review #LLM

Practice

AI Engineer • System Design • hard

Design an AI agent system that can autonomously browse the web and complete tasks.

#Agents #Tool Use

Practice

AI Engineer • System Design • hard

Design an AI-powered customer support chatbot for an e-commerce platform.

#Chatbot #LLM

Practice

AI Engineer • System Design • hard

Design a document question-answering system using RAG.

#RAG #Vector Search

Practice

AI Engineer • Technical • hard

What is hallucination in LLMs? How do you detect and mitigate it?

#Hallucination #Safety

Practice

AI Engineer • Technical • medium

What is streaming response from an LLM API? How do you implement it in a web app?

#Streaming #API

Practice

AI Engineer • Technical • medium

Explain structured output generation from LLMs (JSON mode, Instructor library).

#Structured Output #JSON

Practice

AI Engineer • Technical • hard

Explain the difference between GPT, BERT, and T5 architectures.

#GPT #BERT #T5

Practice

AI Engineer • Technical • medium

What is prompt engineering? What are few-shot, zero-shot, and chain-of-thought prompting?

#Prompt Engineering #Few-Shot

Practice

AI Engineer • Technical • hard

Explain how RLHF (Reinforcement Learning from Human Feedback) improves LLMs.

#RLHF #Alignment

Practice

AI Engineer • Technical • hard

What is RAG (Retrieval-Augmented Generation)? When would you use it over fine-tuning?

#RAG #Fine-Tuning

Practice

AI Engineer • Technical • medium

Explain the difference between fine-tuning and in-context learning.

#Fine-Tuning #ICL

Practice

AI Engineer • Technical • medium

What is token context window? How do you handle documents longer than the context limit?

#Context Window #Chunking

Practice

AI Engineer • Technical • hard

Explain positional encoding in transformers. What are the differences between absolute and rotary position embeddings?

#Positional Encoding #RoPE

Practice

AI Engineer • Technical • medium

Explain the difference between autoregressive and masked language modeling.

#Autoregressive #Masked LM

Practice

AI Engineer • Technical • hard

What is a mixture of experts (MoE) architecture? How does it scale?

#MoE #Scaling

Practice

AI Engineer • Technical • hard

Explain how vector similarity search works. What are HNSW and IVF indices?

#HNSW #Similarity Search

Practice

AI Engineer • Technical • medium

Compare vector databases: Pinecone, Weaviate, Qdrant, and pgvector.

#Vector DB #Embeddings

Practice

AI Engineer • Technical • medium

How do you choose the right embedding model for a domain-specific search task?

#Embedding Models #Search

Practice

AI Engineer • Technical • medium

What is semantic search? How does it differ from keyword-based search?

#Semantic Search #NLP

Practice

AI Engineer • Technical • hard

Explain the difference between dense and sparse retrieval in RAG.

#Dense Retrieval #BM25

Practice

AI Engineer • Technical • hard

How do you evaluate retrieval quality in a RAG system?

#Evaluation #Retrieval

Practice

AI Engineer • Technical • hard

How do you evaluate the quality of an LLM-generated response?

#LLM Evaluation #RAGAS

Practice

AI Engineer • Technical • hard

What is AI alignment? What are the key safety concerns with large-scale AI deployment?

#Alignment #Safety

Practice

AI Engineer • Technical • hard

Explain the concept of AI bias. How do you detect and mitigate it in production?

#Bias #Fairness

Practice

AI Engineer • Technical • hard

What is Constitutional AI? How does Anthropic use it?

#Constitutional AI #Anthropic

Practice

AI Engineer • Technical • hard

How do you red-team an AI system?

#Red Teaming #Security

Practice

AI Engineer • Technical • medium

What are guardrails in LLM applications? How do they work?

#Guardrails #Output Filtering

Practice

AI Engineer • Technical • medium

How do you integrate OpenAI API or Gemini API into a production application?

#OpenAI #Gemini

Practice

AI Engineer • Technical • medium

What is LangChain? What are its key components (Chains, Agents, Tools)?

#LangChain #Agents

Practice

AI Engineer • Technical • hard

Explain function calling / tool use in LLMs. How do you implement it?

#Function Calling #Tool Use

Practice

AI Engineer • Technical • medium

How do you manage LLM API rate limits and costs in production?

#Rate Limiting #Cost

Practice

Cloud Engineer • Behavioral • hard

Tell me about a major cloud outage you experienced. How did you respond?

#Outage #On-Call

Practice

Cloud Engineer • Behavioral • hard

Describe a time you migrated a critical workload to the cloud with zero downtime.

#Cloud Migration

Practice

Cloud Engineer • Behavioral • easy

How do you stay updated with new cloud services and features?

#Continuous Learning

Practice

Cloud Engineer • Behavioral • medium

Describe a situation where you had to choose between two cloud architectures. How did you decide?

#Architecture #Tradeoffs

Practice

Cloud Engineer • Behavioral • medium

Describe your experience with incident post-mortems. What do you include?

#Post-Mortem #Learning

Practice

Cloud Engineer • Behavioral • medium

How do you communicate a complex cloud architecture to non-technical stakeholders?

#Stakeholders

Practice

Cloud Engineer • Behavioral • medium

Tell me about a time you improved the reliability of a cloud-based data system.

#SRE #Impact

Practice

Cloud Engineer • Behavioral • medium

Tell me about a time you had to push back on a stakeholder who wanted to deploy a feature that you believed compromised system reliability or security.

#Communication #Stakeholder Management #Security #Reliability

Practice

Cloud Engineer • Behavioral • medium

Tell me about a time you significantly reduced cloud infrastructure costs.

#FinOps #Impact

Practice

Cloud Engineer • Behavioral • medium

Microsoft heavily emphasizes a 'growth mindset'. Tell me about a time you had to learn a completely new technology on the fly to solve a critical infrastructure issue.

#Growth Mindset #Adaptability #Problem Solving #Continuous Learning

Practice

Cloud Engineer • Behavioral • medium

Describe a time when a production deployment caused a major incident. How did you handle the immediate triage, and what did you contribute to the post-mortem?

#Incident Management #Post-mortem #Accountability #CI/CD

Practice

Cloud Engineer • Coding • easy

Write a script (Python or PowerShell) that queries an Azure subscription, identifies all unattached managed disks, and outputs their names and sizes to a CSV file.

#PowerShell #Python #Azure CLI #Azure SDK #Cost Optimization

Practice

Cloud Engineer • Coding • medium

Design and implement a data structure for a Least Recently Used (LRU) cache. It should support get and put operations in O(1) time complexity.

#Hash Map #Doubly Linked List #Caching

Practice

Cloud Engineer • Coding • medium

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

#Arrays #Sorting #Time Complexity

Practice

Cloud Engineer • System Design • hard

How would you set up a streaming data pipeline on GCP using Pub/Sub and Dataflow?

#GCP #Pub/Sub #Dataflow

Practice

Cloud Engineer • System Design • hard

Design a data lake on AWS using S3, Glue, and Athena.

#AWS #S3 #Athena

Practice

Cloud Engineer • System Design • hard

Design a highly available, multi-region web application on Azure that can withstand a complete regional outage.

#Azure Traffic Manager #Azure Front Door #Availability Zones #Cosmos DB #Disaster Recovery

Practice

Cloud Engineer • System Design • hard

How would you design a disaster recovery strategy for a stateful microservices architecture hosted on AKS, ensuring an RPO of less than 5 minutes?

#AKS #Disaster Recovery #StatefulSets #Velero #Azure NetApp Files

Practice

Cloud Engineer • System Design • hard

How do you implement disaster recovery for a cloud data warehouse?

#DR #RTO #RPO

Practice

Cloud Engineer • System Design • hard

Design a scalable telemetry ingestion pipeline for millions of IoT devices. The system needs to process events in real-time and store them for long-term analytical querying.

#Azure IoT Hub #Event Hubs #Stream Analytics #Cosmos DB #Azure Data Explorer

Practice

Cloud Engineer • System Design • hard

How would you architect a data platform that reduces spend by 40% without impacting performance?

#FinOps #Cloud

Practice

Cloud Engineer • Technical • medium

How do cloud IAM roles and policies work? Explain least-privilege principle.

#IAM #Permissions

Practice

Cloud Engineer • Technical • medium

What is AWS PrivateLink? When would you use it?

#PrivateLink #VPC

Practice

Cloud Engineer • Technical • hard

How would you implement network segmentation for a multi-tier application?

#Security #Subnets

Practice

Cloud Engineer • Technical • medium

What are SLOs, SLAs, and SLIs? How do you define them for a data platform?

#SLO #Reliability

Practice

Cloud Engineer • Technical • hard

Explain chaos engineering. How would you implement it for a data pipeline?

#Chaos Engineering #Fault Injection

Practice

Cloud Engineer • Technical • medium

How do you do capacity planning for a cloud data platform?

#Scaling #Planning

Practice

Cloud Engineer • Technical • easy

What is a runbook? How do you create effective runbooks for data infrastructure?

#Runbook #On-Call

Practice

Cloud Engineer • Technical • medium

Explain the three pillars of observability: logs, metrics, and traces.

#Logs #Metrics #Traces

Practice

Cloud Engineer • Technical • medium

How would you set up CloudWatch dashboards for a data pipeline?

#CloudWatch #AWS

Practice

Cloud Engineer • Technical • medium

What is OpenTelemetry? How does it standardize observability?

#OpenTelemetry #Tracing

Practice

Cloud Engineer • Technical • medium

How do you configure Azure Monitor and Log Analytics to detect a specific error string in application logs and automatically trigger an Azure Automation runbook to restart the service?

#Azure Monitor #Log Analytics #KQL #Azure Automation #Alerting

Practice

Cloud Engineer • Technical • easy

Compare Azure SQL Database, Azure SQL Managed Instance, and SQL Server on Azure VMs. What are the key decision factors for migrating an on-premises database to one of these?

#Azure SQL #PaaS vs IaaS #Database Migration #High Availability

Practice

Cloud Engineer • Technical • medium

Explain how System-Assigned and User-Assigned Managed Identities work in Azure. How do they improve security compared to using Service Principals with client secrets?

#Entra ID #Managed Identity #RBAC #Azure Key Vault #Authentication

Practice

Cloud Engineer • Technical • medium

Walk me through your troubleshooting steps if a pod in an Azure Kubernetes Service (AKS) cluster is stuck in a CrashLoopBackOff state.

#AKS #Kubernetes #Troubleshooting #Docker #Logs

Practice

Cloud Engineer • Technical • medium

How do you detect and remediate infrastructure drift in an Azure environment when using Infrastructure as Code tools like Bicep or Terraform?

#Terraform #Bicep #State Management #Azure Policy #GitOps

Practice

Cloud Engineer • Technical • medium

Explain the architectural differences between Azure ExpressRoute and a Site-to-Site VPN. In what scenarios would you recommend one over the other?

#ExpressRoute #VPN Gateway #BGP #Network Security #Hybrid Cloud

Practice

Cloud Engineer • Technical • medium

What is Azure Kubernetes Service (AKS)? How does it differ from EKS?

#AKS #EKS

Practice

Cloud Engineer • Technical • hard

How do you design for high availability in Azure using availability zones?

#HA #Availability Zones

Practice

Cloud Engineer • Technical • medium

Explain Azure Active Directory and its role in enterprise IAM.

#AAD #IAM

Practice

Cloud Engineer • Technical • hard

Compare AWS, GCP, and Azure for a data-intensive workload. What are the key differentiators?

#AWS #GCP #Azure

Practice

Cloud Engineer • Technical • medium

What is the shared responsibility model in cloud security?

#Cloud Security #IAM

Practice

Cloud Engineer • Technical • easy

Explain IaaS, PaaS, and SaaS with examples.

#IaaS #PaaS #SaaS

Practice

Cloud Engineer • Technical • hard

What is a VPC (Virtual Private Cloud)? How do you design a secure VPC architecture?

#VPC #Security

Practice

Cloud Engineer • Technical • easy

Explain the difference between regions, availability zones, and edge locations.

#Regions #AZs

Practice

Cloud Engineer • Technical • medium

How does auto-scaling work? What are the different scaling strategies?

#Auto-Scaling #EC2

Practice

Cloud Engineer • Technical • medium

What is a cloud-native application? How does it differ from a lifted-and-shifted one?

#Cloud Native #Migration

Practice

Cloud Engineer • Technical • hard

Explain multi-cloud vs hybrid cloud architectures and their tradeoffs.

#Multi-Cloud #Hybrid

Practice

Cloud Engineer • Technical • hard

Explain Kubernetes architecture: control plane, nodes, pods, and services.

#K8s #Containers

Practice

Cloud Engineer • Technical • hard

What is a Kubernetes Operator and when would you build one?

#Operators #CRD

Practice

Cloud Engineer • Technical • hard

How does container networking work in Kubernetes?

#Networking #CNI

Practice

Cloud Engineer • Technical • medium

Explain Kubernetes resource requests vs limits. What happens if a pod exceeds its memory limit?

#Resources #OOM

Practice

Cloud Engineer • Technical • hard

What is a service mesh? Explain how Istio works.

#Istio #Service Mesh

Practice

Cloud Engineer • Technical • hard

How would you set up horizontal pod autoscaling based on custom metrics?

#HPA #Custom Metrics

Practice

Cloud Engineer • Technical • medium

Explain the difference between Docker and containerd.

#Docker #containerd

Practice

Cloud Engineer • Technical • medium

How does a Kubernetes Ingress controller work?

#Ingress #Load Balancing

Practice

Cloud Engineer • Technical • hard

Explain Terraform's state management. What happens if the state file is corrupted?

#IaC #State

Practice

Cloud Engineer • Technical • medium

What is the difference between Terraform and Pulumi?

#Terraform #Pulumi

Practice

Cloud Engineer • Technical • medium

How do you manage secrets in cloud infrastructure? (HashiCorp Vault, AWS Secrets Manager)

#Secrets Management #Vault

Practice

Cloud Engineer • Technical • medium

Explain idempotency in infrastructure provisioning.

#Idempotency #Terraform

Practice

Cloud Engineer • Technical • hard

How do you handle Terraform state across multiple teams?

#State Management #Collaboration

Practice

Cloud Engineer • Technical • hard

Compare AWS EMR, GCP Dataproc, and Azure HDInsight for Spark workloads.

#EMR #Dataproc #Spark

Practice

Cloud Engineer • Technical • medium

Explain the difference between AWS Lambda and EC2 for data processing.

#Lambda #Serverless

Practice

Cloud Engineer • Technical • hard

What is BigQuery Slots? How do you optimize BigQuery query costs?

#GCP #Cost

Practice

Cloud Engineer • Technical • medium

Explain AWS S3 storage classes and lifecycle policies.

#S3 #Cost

Practice

Cloud Engineer • Technical • medium

How does AWS Glue Data Catalog work with Athena?

#Glue #Athena

Practice

Cloud Engineer • Technical • hard

What is zero-trust networking? How do you implement it on cloud?

#Zero Trust #Networking

Practice

Cloud Engineer • Technical • medium

Explain TLS/SSL termination in a cloud load balancer.

#TLS #Load Balancer

Practice

Data Analyst • Behavioral • medium

How do you handle a situation where a stakeholder challenges your analysis?

#Stakeholders #Confidence

Practice

Data Analyst • Behavioral • medium

Describe a time you found an insight that was counterintuitive.

#Curiosity

Practice

Data Analyst • Behavioral • hard

Tell me about a time you had incomplete data but still needed to deliver analysis.

#Ambiguity

Practice

Data Analyst • Behavioral • medium

How do you prioritize analytical requests when multiple teams need you?

#Time Management

Practice

Data Analyst • Behavioral • medium

Describe a dashboard you built that was widely adopted. What made it successful?

#Visualization

Practice

Data Analyst • Behavioral • medium

Tell me about a time you discovered data quality issues mid-analysis. What did you do?

#Problem Solving

Practice

Data Analyst • Behavioral • easy

How do you ensure your analyses are reproducible?

#Reproducibility

Practice

Data Analyst • Behavioral • medium

Tell me about an analysis that changed a major business decision.

#Business Impact #Influence

Practice

Data Analyst • Coding • hard

Write a SQL query to find customers who made purchases in both January and February but not March.

#Set Operations

Practice

Data Analyst • Coding • hard

Write a SQL query to calculate the rolling 28-day average session duration per user.

#Rolling Average #Sessions

Practice

Data Analyst • Coding • hard

How would you build a cohort analysis for user retention in SQL?

#Cohort Analysis #Retention

Practice

Data Analyst • Coding • medium

Write a SQL query to calculate month-over-month revenue growth.

#Revenue #Growth Analytics

Practice

Data Analyst • Coding • medium

How would you merge two large DataFrames efficiently in pandas?

#Pandas #Merging

Practice

Data Analyst • Coding • medium

Describe how to detect and handle outliers in a dataset using Python.

#Outliers #Data Cleaning

Practice

Data Analyst • Coding • easy

Write Python code to load a CSV, clean missing values, and compute summary statistics.

#Data Cleaning #Pandas

Practice

Data Analyst • Coding • medium

How would you use pandas to compute a 7-day rolling average of sessions?

#Pandas #Time Series

Practice

Data Analyst • Coding • easy

Explain how groupby and agg work in pandas with an example.

#Pandas #GroupBy

Practice

Data Analyst • Coding • hard

How would you detect anomalies in a daily revenue time series using SQL?

#Anomaly Detection #SQL

Practice

Data Analyst • Coding • medium

Explain window functions. Write a query using LAG() to compute day-over-day change.

#Window Functions

Practice

Data Analyst • Coding • hard

What is a funnel query? Write one for a 3-step user onboarding flow.

#Funnel Analysis

Practice

Data Analyst • Coding • medium

What is a pivot table in SQL? How would you implement it without native PIVOT support?

#Pivot #Data Transformation

Practice

Data Analyst • Technical • medium

What is customer lifetime value (LTV)? How would you calculate it?

#LTV #Retention

Practice

Data Analyst • Technical • hard

Daily Active Users dropped 15% yesterday. Walk me through how you'd investigate.

#Root Cause Analysis #Metrics

Practice

Data Analyst • Technical • medium

How do you handle timezone conversions in SQL analytics?

#Timezones #Analytics

Practice

Data Analyst • Technical • easy

Explain the difference between a HAVING clause and a WHERE clause.

#SQL Basics

Practice

Data Analyst • Technical • medium

Describe your process for creating an executive-level analytics presentation.

#Executive Reporting

Practice

Data Analyst • Technical • easy

How do you choose between a bar chart, line chart, and scatter plot?

#Charts #Design

Practice

Data Analyst • Technical • easy

What tools do you use for dashboarding? Compare Tableau, Looker, and Metabase.

#Tableau #Looker

Practice

Data Analyst • Technical • medium

How would you explain statistical significance to a non-technical product manager?

#Storytelling #Statistics

Practice

Data Analyst • Technical • medium

What makes a good data visualization? Walk me through your design principles.

#Design #Communication

Practice

Data Analyst • Technical • hard

How do you handle multiple metrics in an A/B test (metric tradeoffs)?

#Multiple Metrics #Tradeoffs

Practice

Data Analyst • Technical • medium

What is a novelty effect in experimentation? How do you account for it?

#Novelty Effect #Bias

Practice

Data Analyst • Technical • hard

A/B test shows p=0.04, but the effect size is tiny. Would you ship?

#Practical Significance #Decision Making

Practice

Data Analyst • Technical • hard

What sample size do you need for an A/B test? How do you calculate it?

#Sample Size #Power

Practice

Data Analyst • Technical • hard

Explain how you'd set up an A/B test to validate a new checkout flow.

#A/B Testing #Statistics

Practice

Data Analyst • Technical • hard

How would you measure the impact of a pricing change on revenue?

#Pricing #A/B Test

Practice

Data Analyst • Technical • easy

What is net promoter score (NPS)? How do you analyse NPS trends?

#NPS #Customer Satisfaction

Practice

Data Analyst • Technical • hard

What metrics would you use to measure the health of a marketplace?

#Marketplace #Supply & Demand

Practice

Data Analyst • Technical • medium

How would you build a dashboard to monitor e-commerce funnel health?

#Visualization #Funnel

Practice

Data Analyst • Technical • hard

Explain the concept of attribution modeling. What are last-click vs multi-touch models?

#Marketing Analytics

Practice

Data Analyst • Technical • easy

What is ARPU (Average Revenue Per User)? How do you segment ARPU analysis?

#ARPU #Revenue

Practice

Data Analyst • Technical • medium

How would you measure the success of a new feature launch?

#Feature Success #Metrics

Practice

Data Analyst • Technical • easy

Explain the difference between DAU, WAU, and MAU. Which is most useful and when?

#Engagement #KPIs

Practice

Data Engineer • Behavioral • easy

Describe a situation where you had to learn a completely new technology or framework very quickly to deliver a critical project. How did you approach the learning process?

#Growth Mindset #Adaptability #Continuous Learning

Practice

Data Engineer • Behavioral • medium

Tell me about a time you had to push back on a Product Manager or stakeholder regarding a technical constraint or unrealistic deadline. How did you handle it?

#Communication #Stakeholder Management #Conflict Resolution

Practice

Data Engineer • Behavioral • medium

Tell me about a time you made a significant mistake or failed to meet a deadline on a data project. What was the impact, and how did you communicate this to your team and stakeholders?

#Accountability #Transparency #Problem Solving

Practice

Data Engineer • Behavioral • easy

How do you stay current with rapidly evolving data engineering tools and practices?

#Growth Mindset

Practice

Data Engineer • Behavioral • easy

Describe your experience mentoring junior data engineers.

#Mentoring #Collaboration

Practice

Data Engineer • Behavioral • medium

Tell me about a time you onboarded a new data source that had significant quality issues.

#Problem Solving

Practice

Data Engineer • Behavioral • hard

Describe how you've balanced technical debt vs. new feature development in a data platform.

#Prioritization

Practice

Data Engineer • Behavioral • medium

Tell me about a time you significantly improved the performance of a data system.

#Performance #Optimization

Practice

Data Engineer • Behavioral • medium

How do you handle disagreements with data analysts or scientists who want features that compromise pipeline reliability?

#Conflict Resolution

Practice

Data Engineer • Behavioral • medium

Describe a situation where a data pipeline you owned went down in production. How did you handle it?

#On-Call #Problem Solving

Practice

Data Engineer • Behavioral • medium

Tell me about a time you simplified a complex data platform decision across multiple teams.

#Communication #Stakeholders

Practice

Data Engineer • Coding • medium

Write a SQL query to compute a 7-day rolling average of daily sales.

#Window Functions #Analytics

Practice

Data Engineer • Coding • medium

Write a SQL query to find the second highest salary per department.

#Window Functions #SQL

Practice

Data Engineer • Coding • medium

Given a massive text file containing Azure server logs, write a Python script to find the top 10 most frequent IP addresses. The file is larger than the available RAM.

#File I/O #Hash Maps #Heaps #Memory Management

Practice

Data Engineer • Coding • medium

Write a SQL query to find the top 3 highest-grossing products in each product category from the `microsoft_store_sales` table.

#Window Functions #Ranking #Aggregations

Practice

Data Engineer • Coding • medium

Given an array of user session time intervals (start_time, end_time) on a Microsoft service, write a Python function to merge all overlapping sessions and return the consolidated active time blocks.

#Arrays #Sorting #Intervals

Practice

Data Engineer • Coding • hard

Write a SQL query to find the maximum number of consecutive days a user logged into Office 365. You are given a table `user_logins` with columns `user_id` and `login_date`.

#Window Functions #Gaps and Islands #CTEs

Practice

Data Engineer • System Design • medium

Design a batch processing system to aggregate daily billing data for Azure customers. The data arrives as millions of small JSON files in Azure Data Lake Storage (ADLS) Gen2. How do you process this efficiently and load it into a reporting layer?

#Batch Processing #Azure Data Factory #ADLS Gen2 #Small Files Problem

Practice

Data Engineer • System Design • hard

Design a data model for an e-commerce platform tracking orders, users, and products.

#ER Modeling #Dimensional Modeling

Practice

Data Engineer • System Design • hard

Design a Data Lake architecture for a global enterprise that ensures strict GDPR compliance (Right to be Forgotten) and Role-Based Access Control (RBAC) down to the row/column level.

#Data Governance #GDPR #Delta Lake #Azure Purview

Practice

Data Engineer • System Design • hard

Design a real-time telemetry ingestion pipeline for Xbox Live. The system needs to handle millions of events per second, perform real-time aggregations for live leaderboards, and store raw data for long-term historical analysis.

#Azure Event Hubs #Stream Analytics #Cosmos DB #Lambda Architecture

Practice

Data Engineer • System Design • hard

How would you design a real-time anomaly detection pipeline for 100K events/sec?

#Real-Time #Anomaly Detection

Practice

Data Engineer • System Design • hard

How would you design a data warehouse for a ride-sharing company from scratch?

#Architecture #Design

Practice

Data Engineer • System Design • hard

Design an ETL pipeline that ingests 10TB of raw clickstream data daily.

#ETL #Batch Processing

Practice

Data Engineer • System Design • hard

How would you design a data pipeline using Azure Data Factory and Synapse?

#ADF #Synapse

Practice

Data Engineer • System Design • hard

How would you design a data pipeline that needs exactly-once delivery guarantees?

#Exactly-Once #Kafka

Practice

Data Engineer • Technical • hard

What is Microsoft Fabric? How does it unify data and analytics?

#Fabric #Analytics

Practice

Data Engineer • Technical • hard

What is a slowly changing dimension (SCD)? Describe SCD Type 1, 2, and 3 with examples.

#SCD #Dimensional Modeling

Practice

Data Engineer • Technical • hard

How would you optimize a SQL query that is running slowly on a 1 billion row table?

#Query Optimization #Indexing

Practice

Data Engineer • Technical • medium

Explain the difference between RANK(), DENSE_RANK(), and ROW_NUMBER().

#Window Functions #SQL

Practice

Data Engineer • Technical • medium

What is a materialized view? How does it differ from a regular view?

#Materialized Views #Performance

Practice

Data Engineer • Technical • hard

Describe partitioning strategies in a data warehouse. When would you use range vs hash partitioning?

#Partitioning #Performance

Practice

Data Engineer • Technical • medium

What are CTEs (Common Table Expressions) and how do they differ from subqueries?

#CTEs #SQL

Practice

Data Engineer • Technical • medium

Explain ACID properties. Which databases sacrifice ACID for performance and why?

#ACID #Distributed Systems

Practice

Data Engineer • Technical • hard

How do you handle late-arriving data in a streaming pipeline?

#Kafka #Watermarks

Practice

Data Engineer • Technical • medium

What is idempotency and why is it critical in data pipelines?

#Idempotency #Data Quality

Practice

Data Engineer • Technical • hard

Explain the Lambda architecture. What are its tradeoffs vs Kappa architecture?

#Lambda #Kappa #Streaming

Practice

Data Engineer • Technical • hard

What is backfilling? How do you handle a backfill of 2 years of historical data without impacting production?

#Backfill #Airflow

Practice

Data Engineer • Technical • medium

Describe how you'd implement circuit breakers in a data pipeline.

#Circuit Breakers #Fault Tolerance

Practice

Data Engineer • Technical • medium

How do you monitor data pipeline health in production? What metrics do you track?

#Monitoring #Alerting

Practice

Data Engineer • Technical • medium

What is Apache Airflow? How does it differ from Prefect or Dagster?

#Airflow #Prefect #Dagster

Practice

Data Engineer • Technical • easy

Explain the difference between push-based and pull-based data ingestion.

#Push #Pull #CDC

Practice

Data Engineer • Technical • hard

Explain how Apache Spark's execution model works. What is a DAG in Spark?

#Spark #DAG #Distributed Computing

Practice

Data Engineer • Technical • hard

What is data skew in Spark? How do you diagnose and fix it?

#Data Skew #Performance

Practice

Data Engineer • Technical • hard

Explain the difference between map-side and reduce-side joins in MapReduce/Spark.

#Joins #MapReduce

Practice

Data Engineer • Technical • medium

What is Apache Kafka? Explain topics, partitions, consumer groups, and offsets.

#Kafka #Streaming

Practice

Data Engineer • Technical • medium

How does Kafka handle message ordering guarantees?

#Ordering #Partitions

Practice

Data Engineer • Technical • medium

What is the CAP theorem? Give an example of a real-world system tradeoff.

#CAP #Consistency #Availability

Practice

Data Engineer • Technical • medium

Explain how Parquet and ORC file formats work and when you'd use each.

#Parquet #ORC #Columnar

Practice

Data Engineer • Technical • hard

What is Delta Lake? How does it provide ACID transactions on data lakes?

#Delta Lake #ACID #Time Travel

Practice

Data Engineer • Technical • medium

Explain compaction in Delta Lake / Iceberg. Why is it important?

#Compaction #Performance

Practice

Data Engineer • Technical • medium

What is the star schema vs snowflake schema? When would you use each?

#Star Schema #Snowflake Schema

Practice

Data Engineer • Technical • hard

What is Data Vault methodology? How does it differ from Kimball?

#Data Vault #Kimball

Practice

Data Engineer • Technical • medium

Explain the concept of a data lakehouse. What are its advantages over a traditional data warehouse?

#Data Lakehouse #Data Warehouse

Practice

Data Engineer • Technical • hard

How do you handle schema evolution in a data pipeline without breaking downstream consumers?

#Schema Evolution #Backward Compatibility

Practice

Data Engineer • Technical • medium

What is a medallion architecture (Bronze/Silver/Gold)?

#Medallion #Data Lake

Practice

Data Engineer • Technical • medium

How do you implement data quality checks in a production pipeline?

#Great Expectations #Data Validation

Practice

Data Engineer • Technical • medium

What is data lineage and why is it important? How do you implement it?

#Lineage #Metadata

Practice

Data Engineer • Technical • hard

How would you detect and handle data drift in a production system?

#Data Drift #Monitoring

Practice

Data Engineer • Technical • medium

What is PII (Personally Identifiable Information) and how do you handle it in a data pipeline?

#PII #Privacy #Compliance

Practice

Data Engineer • Technical • medium

Explain the concept of a data catalog. What tools have you used?

#Data Catalog #Metadata

Practice

Data Engineer • Technical • hard

Compare AWS Redshift, Google BigQuery, and Snowflake for a petabyte-scale warehouse.

#Redshift #BigQuery #Snowflake

Practice

Data Engineer • Technical • hard

How does BigQuery handle large joins efficiently? What is its columnar storage approach?

#BigQuery #Columnar Storage

Practice

Data Engineer • Technical • medium

Explain the difference between S3, HDFS, and GCS for data storage.

#S3 #HDFS #GCS

Practice

Data Engineer • Technical • medium

How would you reduce costs in a cloud-based data platform?

#Cloud #Cost

Practice

Data Engineer • Technical • medium

What is infrastructure as code (IaC)? Have you used Terraform for data infrastructure?

#Terraform #IaC

Practice

Data Engineer • Technical • medium

Explain the difference between OLAP and OLTP systems. When would you use each?

#OLAP #OLTP #Databases

Practice

Data Engineer • Technical • medium

Explain Azure Event Hubs vs Azure Service Bus for streaming.

#Event Hubs #Streaming

Practice

Data Engineer • Technical • hard

How would you migrate an on-premise data warehouse to Azure Synapse?

#Synapse #Azure

Practice

Data Engineer • Technical • hard

You have a PySpark job running on Azure Databricks that joins a massive 10TB fact table with a 500MB dimension table. The job is taking hours to complete and frequently fails with OutOfMemory errors. How would you optimize this?

#PySpark #Broadcast Joins #Data Skew #Performance Tuning

Practice

Data Engineer • Technical • medium

Explain the architectural and use-case differences between Azure Synapse Analytics and Azure Databricks. In what scenario would you explicitly choose one over the other?

#Azure Synapse #Azure Databricks #Data Warehousing #Lakehouse

Practice

Data Engineer • Technical • medium

Design a dimensional data model (Star Schema) for Microsoft Teams call analytics. We need to analyze call drops, average call duration, and participant counts by region, device type, and time.

#Star Schema #Fact Tables #Dimension Tables #Granularity

Practice

Data Engineer • Technical • hard

How does Apache Spark handle memory management? Specifically, explain the difference between execution memory and storage memory, and how the unified memory manager balances them.

#Spark Architecture #Memory Management #Distributed Computing

Practice

Data Engineer • Technical • medium

In a traditional Data Warehouse ETL pipeline, how do you handle 'late-arriving dimensions' (when fact data arrives before the corresponding dimension data)?

#ETL #Data Warehousing #Data Integrity

Practice

Data Scientist • Behavioral • hard

Describe a time you used data to challenge a widely held assumption in your organization.

#Influence #Analytics

Practice

Data Scientist • Behavioral • hard

Tell me about a time you had to push back on a business request for an analysis that would be misleading.

#Ethics #Communication

Practice

Data Scientist • Behavioral • medium

Describe a project where you had to iterate significantly on your initial approach.

#Iteration #Learning

Practice

Data Scientist • Behavioral • medium

Describe a situation where your data analysis contradicted the prevailing business strategy or a senior leader's hypothesis. How did you communicate your findings?

#Influencing without Authority #Communication #Data Storytelling

Practice

Data Scientist • Behavioral • easy

Tell me about a time you had to learn a completely new technology or framework to solve a complex data problem. How did you approach the learning process?

#Growth Mindset #Adaptability #Continuous Learning

Practice

Data Scientist • Behavioral • medium

How do you prioritize between multiple data science requests from different teams?

#Stakeholder Management

Practice

Data Scientist • Behavioral • hard

Tell me about a time your model failed in production. What did you learn?

#Production #MLOps

Practice

Data Scientist • Behavioral • medium

How do you approach ethical considerations in ML model building?

#Fairness #Bias

Practice

Data Scientist • Behavioral • medium

Tell me about a time you had to push back on a product manager or stakeholder who wanted to launch a machine learning model that you knew wasn't ready for production.

#Communication #Stakeholder Management #Integrity

Practice

Data Scientist • Behavioral • medium

Tell me about a data science project where the results surprised you. What did you do?

#Analytical Thinking

Practice

Data Scientist • Behavioral • medium

Describe how you communicated a complex model result to a non-technical stakeholder.

#Storytelling

Practice

Data Scientist • Coding • medium

Given an array of user session time intervals on an Xbox console, where intervals are represented as [start_time, end_time], write a function to merge all overlapping sessions.

#Arrays #Sorting #Intervals

Practice

Data Scientist • Coding • medium

Write a SQL query to find the top 3 departments with the highest number of daily active Microsoft Teams users over the last 30 days. Assume you have a 'user_activity' table and a 'user_directory' table.

#Joins #Aggregations #Window Functions

Practice

Data Scientist • Coding • medium

Write a query to identify duplicate records and deduplicate them.

#Deduplication #Data Quality

Practice

Data Scientist • Coding • medium

Write a Python function to calculate the 7-day moving average of Daily Active Users (DAU) given a list of dictionaries containing 'date' and 'user_count'. Handle missing dates by assuming 0 users.

#Data Manipulation #Time Series #Sliding Window

Practice

Data Scientist • Coding • hard

Write a SQL query to calculate 30-day user retention.

#Retention #Analytics

Practice

Data Scientist • Coding • hard

How would you write a funnel analysis query in SQL?

#Funnel #Analytics

Practice

Data Scientist • Coding • hard

Given a table of Azure resource provisioning events (event_id, region, start_timestamp, end_timestamp), write a SQL query to calculate the median time to provision a virtual machine for each region.

#Percentiles #Window Functions #Date/Time Functions

Practice

Data Scientist • Coding • medium

Given a stream of telemetry events representing feature usage in Excel, write a Python function to find the top K most frequently used features in real-time.

#Heaps #Hash Maps #Streaming Data

Practice

Data Scientist • System Design • hard

How would you design a recommendation engine for Xbox Game Pass to suggest new games to users?

#Collaborative Filtering #Deep Learning #Cold Start #Personalization

Practice

Data Scientist • System Design • hard

Design an anomaly detection system to identify potential DDoS attacks on Azure cloud infrastructure using network traffic logs.

#Anomaly Detection #Streaming Architecture #Time Series Analysis

Practice

Data Scientist • System Design • hard

Design an auto-complete and next-word prediction feature for Microsoft Word. How would you scale it to serve millions of users with low latency while preserving user privacy?

#NLP #Transformers #Latency Optimization #Edge Computing #Privacy

Practice

Data Scientist • System Design • hard

Design a feature store. What are its key components?

#Feature Store #MLOps

Practice

Data Scientist • System Design • hard

How would you build and deploy a churn prediction model?

#Churn #MLOps

Practice

Data Scientist • System Design • hard

Design a real-time fraud detection system for a payments platform.

#Fraud Detection #Real-Time ML

Practice

Data Scientist • System Design • hard

How would you build a recommendation system? Compare collaborative vs content-based filtering.

#Collaborative Filtering #Content-Based

Practice

Data Scientist • Technical • medium

What is embedding? How do word embeddings like Word2Vec and GloVe work?

#Embeddings #Word2Vec

Practice

Data Scientist • Technical • hard

How would you design an experiment to measure the impact of a new ranking algorithm?

#Experimentation #Metrics

Practice

Data Scientist • Technical • medium

What is a confidence interval? How does it differ from a prediction interval?

#Confidence Interval #Intervals

Practice

Data Scientist • Technical • hard

Explain Bayesian vs Frequentist statistics. When would you use each?

#Bayesian #Frequentist

Practice

Data Scientist • Technical • hard

What is the multiple testing problem? How do you correct for it?

#Bonferroni #FDR

Practice

Data Scientist • Technical • medium

How would you detect and mitigate overfitting in a neural network?

#Overfitting #Dropout #Regularization

Practice

Data Scientist • Technical • medium

Explain batch normalization and why it helps training.

#Batch Normalization #Training

Practice

Data Scientist • Technical • medium

Explain the bias-variance tradeoff. How does it influence model selection?

#Bias-Variance #Model Selection

Practice

Data Scientist • Technical • medium

Explain the difference between bagging and boosting.

#Bagging #Boosting

Practice

Data Scientist • Technical • medium

What is a p-value? Why is a p-value of 0.05 not always sufficient?

#Hypothesis Testing #p-value

Practice

Data Scientist • Technical • medium

What is principal component analysis (PCA)? What are its limitations?

#PCA #SVD

Practice

Data Scientist • Technical • medium

Explain the central limit theorem and its importance in data science.

#CLT #Sampling

Practice

Data Scientist • Technical • medium

What is transfer learning? How would you fine-tune a pre-trained model?

#Transfer Learning #Fine-Tuning

Practice

Data Scientist • Technical • medium

Explain how backpropagation works.

#Backpropagation #Neural Networks

Practice

Data Scientist • Technical • hard

What is the vanishing gradient problem? How do LSTM and ResNet address it?

#LSTM #ResNet #Gradients

Practice

Data Scientist • Technical • medium

How would you approach an NLP problem like sentiment analysis from scratch?

#Sentiment Analysis #Text Classification

Practice

Data Scientist • Technical • medium

What is cross-validation? Explain k-fold and stratified k-fold.

#Cross Validation #k-Fold

Practice

Data Scientist • Technical • medium

How do you approach feature selection?

#Feature Selection #LASSO

Practice

Data Scientist • Technical • medium

You are tasked with evaluating a new ranking algorithm for Bing search results. How would you design the A/B test, and what primary and secondary metrics would you track?

#Experimentation #Metrics Definition #Hypothesis Testing

Practice

Data Scientist • Technical • medium

You are building a churn prediction model for Microsoft 365 enterprise subscriptions. The churn rate is highly imbalanced (less than 1%). How do you handle this class imbalance during training and evaluation?

#Imbalanced Data #Sampling Techniques #Evaluation Metrics #Loss Functions

Practice

Data Scientist • Technical • hard

If we run an A/B test on a new collaborative feature in Microsoft Teams, how do you account for network effects (interference) between users in the same organization?

#Network Effects #Cluster Randomization #Experimentation

Practice

Data Scientist • Technical • medium

Explain the mathematical difference between Bagging and Boosting. Which ensemble method would you prefer for predicting ad click-through rates on the Bing Ads network, and why?

#Ensemble Methods #Random Forest #Gradient Boosting #Bias-Variance Tradeoff

Practice

Data Scientist • Technical • medium

Explain the ROC curve and AUC metric. When would you prefer AUC over accuracy?

#ROC #AUC #Metrics

Practice

Data Scientist • Technical • medium

How do you handle class imbalance in a classification problem?

#Imbalanced Data #SMOTE

Practice

Data Scientist • Technical • medium

What is regularization? Explain L1 vs L2 regularization and their effects.

#Regularization #L1 #L2

Practice

Data Scientist • Technical • medium

How does a Random Forest work? What are its hyperparameters and how do you tune them?

#Random Forest #Hyperparameter Tuning

Practice

Data Scientist • Technical • hard

How do you monitor model performance in production? What is model drift?

#Model Drift #Monitoring

Practice

Data Scientist • Technical • easy

What is the difference between Type I and Type II errors?

#Hypothesis Testing #Errors

Practice

Data Scientist • Technical • hard

Explain the transformer architecture. What are attention mechanisms?

#Transformers #Attention #BERT

Practice

Data Scientist • Technical • hard

How do you design an A/B test for a new product feature?

#A/B Testing #Statistics

Practice

Data Scientist • Technical • hard

Explain gradient boosting. How does XGBoost differ from a standard gradient boosting machine?

#Gradient Boosting #XGBoost

Practice

Data Scientist • Technical • easy

Explain the difference between INNER JOIN, LEFT JOIN, and CROSS JOIN.

#Joins #SQL

Practice

Data Scientist • Technical • medium

How would you detect and handle multicollinearity in a regression model?

#Multicollinearity #Regression

Practice

Data Scientist • Technical • hard

Explain the curse of dimensionality and its implications for ML models.

#Dimensionality #Feature Engineering

Practice

Data Scientist • Technical • easy

What is an experiment holdout group?

#Holdout #Control Group

Practice

Data Scientist • Technical • hard

How would you identify the root cause of a sudden 20% drop in DAU?

#Root Cause Analysis #Debugging

Practice

Data Scientist • Technical • easy

Explain the difference between a leading indicator and a lagging indicator.

#Metrics #KPIs

Practice

Data Scientist • Technical • medium

How do you choose a north star metric for a product?

#Metrics #Product Strategy

Practice

Data Scientist • Technical • hard

What is a network effect in experimentation? How do you handle SUTVA violation?

#SUTVA #Network Effects

Practice

Machine Learning Engineer • Behavioral • medium

Tell me about a time you had to push back on a product manager or stakeholder because the ML model could not meet their requested latency, accuracy, or resource constraints.

#Communication #Stakeholder Management #Trade-offs

Practice

Machine Learning Engineer • Behavioral • medium

Tell me about a time you deployed a machine learning model into production and it failed or degraded significantly. How did you diagnose the issue, and how did you fix it?

#Growth Mindset #Production ML #Debugging

Practice

Machine Learning Engineer • Coding • medium

Implement a sparse matrix multiplication algorithm. Optimize it for memory usage, assuming these matrices represent large-scale user-item interactions for a recommendation model.

#Arrays #Hash Maps #Math

Practice

Machine Learning Engineer • Coding • medium

Implement a Trie (Prefix Tree) to support autocomplete functionality for a search bar. Include methods to insert a word and return all words that start with a given prefix.

#Trees #Tries #Strings #DFS

Practice

Machine Learning Engineer • Coding • hard

You have K sorted lists of log timestamps from different distributed ML worker nodes. Write a function to merge them into a single sorted list.

#Divide and Conquer #Heaps #Linked Lists

Practice

Machine Learning Engineer • Coding • medium

Given a stream of Bing search queries, write an algorithm to find the top K most frequent queries in the last hour.

#Heaps #Streaming Data #Hash Maps

Practice

Machine Learning Engineer • System Design • hard

Design a distributed training pipeline for a 100-billion parameter language model using Azure Machine Learning. How do you partition the model and data?

#Distributed Training #Model Parallelism #Data Parallelism #ZeRO

Practice

Machine Learning Engineer • System Design • hard

Design a personalized game recommendation system for Xbox Game Pass. How do you handle the cold start problem for new users and new games?

#Recommender Systems #Collaborative Filtering #Cold Start

Practice

Machine Learning Engineer • System Design • medium

Design a real-time abusive content detection system for Microsoft Teams chat. The system must process millions of messages per minute with sub-100ms latency.

#Real-time Processing #NLP #Classification #Microservices

Practice

Machine Learning Engineer • System Design • hard

Design a Retrieval-Augmented Generation (RAG) system for an enterprise version of Microsoft Copilot that indexes internal company documents. How would you handle document chunking, embedding generation, and retrieval latency?

#RAG #LLMs #Vector Databases #Information Retrieval

Practice

Machine Learning Engineer • Technical • medium

How do you evaluate the output of a Generative AI model (like a summarization or code generation tool) when there is no strict ground truth available?

#LLMs #Metrics #Human-in-the-loop

Practice

Machine Learning Engineer • Technical • medium

You are training a large PyTorch model and encounter a CUDA Out of Memory (OOM) error. Walk me through every step you would take to debug and resolve this issue.

#PyTorch #Memory Management #Distributed Training

Practice

Machine Learning Engineer • Technical • hard

Explain the self-attention mechanism in Transformers. What is its time and space complexity, and how do techniques like FlashAttention optimize it?

#Transformers #Attention Mechanism #Optimization

Practice

Machine Learning Engineer • Technical • hard

How would you optimize a trained PyTorch model for low-latency inference on edge devices, such as running a local Copilot feature on a Windows PC?

#ONNX #Quantization #Edge ML #TensorRT

Practice

Machine Learning Engineer • Technical • hard

Explain the difference between LoRA (Low-Rank Adaptation) and QLoRA. When would you choose to use one over the other for fine-tuning a foundational model on Azure ML?

#LLMs #Parameter-Efficient Fine-Tuning #Model Compression

Practice

ML Engineer • Behavioral • medium

Describe a model you deployed to production. What were the biggest challenges?

#Deployment #Challenges

Practice

ML Engineer • Behavioral • medium

How do you decide when a model is 'good enough' to ship?

#Quality #Judgment

Practice

ML Engineer • Behavioral • medium

Tell me about a disagreement you had with a researcher. How did you resolve it?

#Communication

Practice

ML Engineer • Behavioral • hard

Describe a time you had to re-architecture a system because the original ML approach didn't scale.

#Scalability

Practice

ML Engineer • Behavioral • easy

How do you keep up with the rapidly evolving ML landscape?

#Continuous Learning

Practice

ML Engineer • Behavioral • hard

Tell me about a time an ML model caused an unexpected real-world impact.

#Responsibility #AI Safety

Practice

ML Engineer • Behavioral • medium

Describe how you collaborated with data scientists to productionize their research code.

#Research to Production

Practice

ML Engineer • Behavioral • hard

Tell me about a time you had to optimize a model for latency without sacrificing too much accuracy.

#Latency #Accuracy

Practice

ML Engineer • Coding • medium

Implement a sliding window approach to detect anomalies in a time series.

#Anomaly Detection #Time Series

Practice

ML Engineer • Coding • hard

Write a custom PyTorch Dataset and DataLoader for irregular time series data.

#PyTorch #DataLoader

Practice

ML Engineer • Coding • hard

Implement logistic regression with gradient descent in NumPy.

#Logistic Regression #NumPy

Practice

ML Engineer • Coding • hard

Implement a K-means clustering algorithm from scratch in Python.

#K-Means #Clustering

Practice

ML Engineer • Coding • hard

How would you write a batched inference pipeline using Python and Triton server?

#Triton #Batching

Practice

ML Engineer • System Design • hard

Design a training and serving architecture for a large language model at scale.

#Infrastructure #Scale

Practice

ML Engineer • System Design • hard

How would you serve a model that needs to respond in under 10ms?

#Low Latency #Serving

Practice

ML Engineer • System Design • hard

Design YouTube's video recommendation system end to end.

#Recommendations #Ranking

Practice

ML Engineer • System Design • hard

Design a search ranking system for an e-commerce platform.

#Ranking #Relevance

Practice

ML Engineer • System Design • hard

Design a real-time content moderation system.

#NLP #Real-Time

Practice

ML Engineer • System Design • hard

Design a system to retrain models automatically when performance degrades.

#Retraining #Automation

Practice

ML Engineer • System Design • hard

Design a CI/CD pipeline for ML models.

#CI/CD #Deployment

Practice

ML Engineer • System Design • hard

What is a feature store? Design one from scratch.

#Feature Engineering #MLOps

Practice

ML Engineer • System Design • hard

How would you build a personalized ad targeting system?

#Targeting #ML Systems

Practice

ML Engineer • Technical • hard

Explain blue-green deployment vs canary deployment for ML models.

#Blue-Green #Canary

Practice

ML Engineer • Technical • hard

How do you detect data drift vs model drift? How do you respond to each?

#Drift #Production

Practice

ML Engineer • Technical • medium

What is shadow mode deployment in ML?

#Shadow Mode #A/B Testing

Practice

ML Engineer • Technical • medium

Explain model serialization formats: ONNX, TorchScript, SavedModel.

#ONNX #Serialization

Practice

ML Engineer • Technical • medium

What is Kubernetes? How is it used for ML model serving?

#Kubernetes #Serving

Practice

ML Engineer • Technical • hard

How do you optimize GPU utilization during training?

#GPU #Performance

Practice

ML Engineer • Technical • hard

Explain mixed precision training (FP16/BF16). What are the risks?

#Mixed Precision #Performance

Practice

ML Engineer • Technical • medium

What are the differences between PyTorch and TensorFlow for production?

#PyTorch #TensorFlow

Practice

ML Engineer • Technical • medium

How do you profile and debug a slow training run?

#Profiling #Debugging

Practice

ML Engineer • Technical • hard

Explain the RLHF (Reinforcement Learning from Human Feedback) training approach.

#RLHF #Fine-Tuning

Practice

ML Engineer • Technical • hard

What is LoRA (Low-Rank Adaptation)? How does it reduce fine-tuning costs?

#LoRA #Fine-Tuning

Practice

ML Engineer • Technical • hard

What is RAG (Retrieval-Augmented Generation)? Describe its architecture.

#RAG #Vector Search

Practice

ML Engineer • Technical • hard

How would you evaluate an LLM for a production use case?

#Evaluation #Benchmarking

Practice

ML Engineer • Technical • medium

Explain vector databases. What are FAISS, Pinecone, and Weaviate?

#Vector DB #Embeddings

Practice

ML Engineer • Technical • medium

What is model ensembling? When does it help, and when does it hurt?

#Ensembling #Performance

Practice

ML Engineer • Technical • hard

What is quantization in neural networks? How does it reduce inference cost?

#Quantization #Inference

Practice

ML Engineer • Technical • hard

How does Microsoft Copilot use RAG for enterprise document Q&A?

#Copilot #RAG

Practice

ML Engineer • Technical • hard

Explain how Microsoft's Phi models differ from GPT models.

#Phi #GPT

Practice

ML Engineer • Technical • medium

How would you use Azure ML Studio for experiment tracking?

#Azure ML #Tracking

Practice

ML Engineer • Technical • easy

What is the difference between a data scientist and an ML engineer?

#Roles #MLOps

Practice

ML Engineer • Technical • medium

Explain the model training pipeline from raw data to deployment.

#Pipeline #Training

Practice

ML Engineer • Technical • medium

What is the difference between online learning and offline learning?

#Online Learning #Batch Learning

Practice

ML Engineer • Technical • medium

How do you handle missing data in ML model features?

#Imputation #Missing Data

Practice

ML Engineer • Technical • medium

Explain gradient descent variants: batch, stochastic, and mini-batch.

#Gradient Descent #Optimization

Practice

ML Engineer • Technical • medium

What are learning rate schedulers and why are they important?

#Learning Rate #Training

Practice

ML Engineer • Technical • hard

Explain the attention mechanism in transformers with mathematical detail.

#Attention #Transformers

Practice

ML Engineer • Technical • hard

Explain knowledge distillation. When would you use it?

#Distillation #Compression

Practice

ML Engineer • Technical • hard

What is the difference between model parallelism and data parallelism in distributed training?

#Parallelism #Training

Practice

ML Engineer • Technical • medium

How do you version ML models and datasets? What tools do you use?

#Versioning #DVC #MLflow

Practice

Product Manager • Behavioral • hard

Tell me about a time you had to drastically pivot your product roadmap due to a sudden shift in technology or market conditions.

#Roadmapping #Agile #Market Trends #Executive Communication

Practice

Product Manager • Behavioral • hard

Describe a time you used data to make a difficult product decision that went against the intuition of senior leadership.

#Data-Driven Decisions #Managing Up #Courage

Practice

Product Manager • Behavioral • medium

Tell me about a time you had to align multiple stakeholders with conflicting priorities across different organizations.

#Stakeholder Management #Conflict Resolution #Cross-functional Collaboration

Practice

Product Manager • Behavioral • easy

Microsoft's mission is to 'empower every person and every organization on the planet to achieve more.' Tell me about a time you embodied this mission in a product you built.

#Empathy #Inclusive Design #Accessibility

Practice

Product Manager • Behavioral • medium

Tell me about a time you failed to deliver a product or feature on time. What was the impact, and what did you learn?

#Accountability #Project Management #Retrospectives

Practice

Product Manager • Coding • easy

Write a SQL query to find the top 5 enterprise customers by monthly active usage (MAU) of Azure Active Directory over the last 30 days.

#Data Analysis #Aggregations #Database Querying

Practice

Product Manager • System Design • hard

Design a telemetry and monitoring system for Xbox Live multiplayer matchmaking to detect latency spikes and server drops in real-time.

#Data Pipelines #Gaming #High Throughput #Monitoring

Practice

Product Manager • System Design • hard

Design an API rate-limiting system for Azure OpenAI services to prevent abuse while ensuring enterprise customers meet their SLAs.

#Cloud Infrastructure #Scalability #API Management #Distributed Systems

Practice

Product Manager • System Design • hard

Design a real-time notification system for Microsoft Teams that scales to millions of concurrent users without significant latency.

#Microservices #Pub/Sub #Real-time Communication #Scalability

Practice

Product Manager • System Design • hard

Design Microsoft Copilot for Excel. Who is the target user, what are the primary use cases, and how would you prioritize the feature rollout?

#Generative AI #Enterprise Software #User Experience #Prioritization

Practice

Product Manager • Technical • medium

What metrics would you track to evaluate the success and product-market fit of GitHub Copilot?

#Metrics #Developer Tools #AI #Telemetry

Practice

Product Manager • Technical • medium

How would you explain the architecture and benefits of a multi-tenant cloud SaaS application to a non-technical enterprise customer?

#Cloud Computing #SaaS #Architecture #Customer Facing

Practice

Product Manager • Technical • medium

You are launching a new generative AI search feature in Bing. How do you plan the go-to-market (GTM) strategy?

#Marketing #User Acquisition #Search #Risk Management

Practice

Product Manager • Technical • hard

How would you price a new advanced AI security feature being added to Microsoft Defender for Cloud?

#Pricing #Cybersecurity #B2B SaaS #Monetization

Practice

Product Manager • Technical • hard

Microsoft Teams adoption and daily active usage have plateaued post-pandemic. How would you investigate the root cause and what strategies would you implement to increase engagement?

#Growth #Metrics #B2B SaaS #Root Cause Analysis

Practice

Software Engineer • Behavioral • medium

Describe a time when you realized a feature you were building was not going to meet the customer's actual needs. What steps did you take?

#Customer Focus #Agile #Communication

Practice

Software Engineer • Behavioral • medium

Tell me about a time you had a fundamental disagreement with a senior team member on a technical design. How did you navigate the situation, and what was the final outcome?

#Collaboration #Conflict Resolution #Growth Mindset

Practice

Software Engineer • Behavioral • medium

Tell me about a time you had to learn a completely new technology or framework under a tight deadline to deliver a critical project.

#Adaptability #Continuous Learning #Drive for Results

Practice

Software Engineer • Coding • medium

Design a data structure that supports insert, remove, and getRandom operations in O(1) average time complexity.

#Hash Table #Arrays #Design

Practice

Software Engineer • Coding • hard

Given an m x n board of characters and a list of strings words, return all words on the board. Each word must be constructed from letters of sequentially adjacent cells (horizontal/vertical).

#Trie #Depth-First Search #Backtracking

Practice

Software Engineer • Coding • hard

Serialize and deserialize a binary tree. Design an algorithm to encode a tree to a single string and decode it back to the original tree structure.

#Trees #Depth-First Search #Breadth-First Search #Design

Practice

Software Engineer • Coding • medium

Given an array of intervals where intervals[i] = [start_i, end_i], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

#Arrays #Sorting

Practice

Software Engineer • Coding • medium

Given a string s, find the length of the longest substring without repeating characters.

#Sliding Window #Hash Table #Strings

Practice

Software Engineer • Coding • medium

Given the root of a binary tree, return the zigzag level order traversal of its nodes' values. (i.e., from left to right, then right to left for the next level and alternate between).

#Trees #Breadth-First Search #Queues

Practice

Software Engineer • Coding • easy

Given the head of a singly linked list, reverse the list, and return the reversed list.

#Linked Lists #Pointers

Practice

Software Engineer • System Design • hard

Design a real-time collaborative text editor like Microsoft Word Online. Focus on how you would handle concurrent edits from multiple users and maintain document consistency.

#Operational Transformation (OT) #CRDTs #Concurrency #WebSockets

Practice

Software Engineer • System Design • hard

Design the backend presence service for Microsoft Teams (online, offline, away, busy). It needs to handle millions of concurrent users with extremely low latency.

#WebSockets #High Availability #Redis #Fan-out Architecture

Practice

Software Engineer • System Design • hard

Design a distributed file storage and synchronization system like Microsoft OneDrive. How do you handle file chunking, cross-device synchronization, and conflict resolution?

#Distributed Systems #Data Consistency #Block Storage #Concurrency

Practice

Software Engineer • Technical • medium

Explain how Garbage Collection works in C#/.NET. What are the different generations, and how does the GC decide when to collect?

#C# #.NET #Memory Management #Garbage Collection

Practice

Software Engineer • Technical • hard

How would you troubleshoot a severe memory leak in a microservice deployed on Azure Kubernetes Service (AKS) that is causing intermittent OutOfMemory (OOM) exceptions?

#Azure #Kubernetes #Debugging #Profiling

Practice

Microsoft

The Interview Loop

Recruiter Screen (30 min)

Technical Loop (3-4 Rounds)

Interview Question Bank

Tell me about an AI project where you had to balance innovation with reliability.

Describe an AI product you built from scratch. What were the key technical decisions?

Tell me about a time an AI system you built produced unexpected or harmful outputs.

How do you stay current with the fast-moving AI/ML research landscape?

Describe a time you had to choose between using an AI model and a simpler rule-based system.

Tell me about a time you optimized an LLM application for cost or latency.

How do you handle stakeholder uncertainty around AI capabilities and limitations?

Describe a situation where you had to debug a hard-to-reproduce AI model failure.

Write a retry mechanism with exponential backoff for LLM API calls.

Implement a simple RAG pipeline using Python, LangChain, and FAISS.

Write a Python class to manage conversation history for a multi-turn chatbot.

Implement a semantic chunking strategy for long documents.

How would you architect an AI platform that supports 1000 concurrent LLM requests?

Design a real-time AI safety filter for user-generated content.

How would you build a multi-modal AI system that processes both text and images?

Design an AI code review system that integrates with GitHub PRs.

Design an AI agent system that can autonomously browse the web and complete tasks.

Design an AI-powered customer support chatbot for an e-commerce platform.

Design a document question-answering system using RAG.

What is hallucination in LLMs? How do you detect and mitigate it?

What is streaming response from an LLM API? How do you implement it in a web app?

Explain structured output generation from LLMs (JSON mode, Instructor library).

Explain the difference between GPT, BERT, and T5 architectures.

What is prompt engineering? What are few-shot, zero-shot, and chain-of-thought prompting?

Explain how RLHF (Reinforcement Learning from Human Feedback) improves LLMs.

What is RAG (Retrieval-Augmented Generation)? When would you use it over fine-tuning?

Explain the difference between fine-tuning and in-context learning.

What is token context window? How do you handle documents longer than the context limit?

Explain positional encoding in transformers. What are the differences between absolute and rotary position embeddings?

Explain the difference between autoregressive and masked language modeling.

What is a mixture of experts (MoE) architecture? How does it scale?

Explain how vector similarity search works. What are HNSW and IVF indices?

Compare vector databases: Pinecone, Weaviate, Qdrant, and pgvector.

How do you choose the right embedding model for a domain-specific search task?

What is semantic search? How does it differ from keyword-based search?

Explain the difference between dense and sparse retrieval in RAG.

How do you evaluate retrieval quality in a RAG system?

How do you evaluate the quality of an LLM-generated response?

What is AI alignment? What are the key safety concerns with large-scale AI deployment?

Explain the concept of AI bias. How do you detect and mitigate it in production?

What is Constitutional AI? How does Anthropic use it?

How do you red-team an AI system?

What are guardrails in LLM applications? How do they work?

How do you integrate OpenAI API or Gemini API into a production application?

What is LangChain? What are its key components (Chains, Agents, Tools)?

Explain function calling / tool use in LLMs. How do you implement it?

How do you manage LLM API rate limits and costs in production?

Tell me about a major cloud outage you experienced. How did you respond?

Describe a time you migrated a critical workload to the cloud with zero downtime.

How do you stay updated with new cloud services and features?

Describe a situation where you had to choose between two cloud architectures. How did you decide?

Describe your experience with incident post-mortems. What do you include?

How do you communicate a complex cloud architecture to non-technical stakeholders?

Tell me about a time you improved the reliability of a cloud-based data system.

Tell me about a time you had to push back on a stakeholder who wanted to deploy a feature that you believed compromised system reliability or security.

Tell me about a time you significantly reduced cloud infrastructure costs.

Microsoft heavily emphasizes a 'growth mindset'. Tell me about a time you had to learn a completely new technology on the fly to solve a critical infrastructure issue.

Describe a time when a production deployment caused a major incident. How did you handle the immediate triage, and what did you contribute to the post-mortem?

Write a script (Python or PowerShell) that queries an Azure subscription, identifies all unattached managed disks, and outputs their names and sizes to a CSV file.

Design and implement a data structure for a Least Recently Used (LRU) cache. It should support get and put operations in O(1) time complexity.

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

How would you set up a streaming data pipeline on GCP using Pub/Sub and Dataflow?

Design a data lake on AWS using S3, Glue, and Athena.

Design a highly available, multi-region web application on Azure that can withstand a complete regional outage.

How would you design a disaster recovery strategy for a stateful microservices architecture hosted on AKS, ensuring an RPO of less than 5 minutes?

How do you implement disaster recovery for a cloud data warehouse?

Design a scalable telemetry ingestion pipeline for millions of IoT devices. The system needs to process events in real-time and store them for long-term analytical querying.

How would you architect a data platform that reduces spend by 40% without impacting performance?

How do cloud IAM roles and policies work? Explain least-privilege principle.

What is AWS PrivateLink? When would you use it?

How would you implement network segmentation for a multi-tier application?

What are SLOs, SLAs, and SLIs? How do you define them for a data platform?

Explain chaos engineering. How would you implement it for a data pipeline?

How do you do capacity planning for a cloud data platform?

What is a runbook? How do you create effective runbooks for data infrastructure?