How Transformer Models Work: Attention Mechanism Explained
Transformers are the architecture behind GPT, BERT, Claude, and every other major language model. Understanding how they work — especially […]
AI/ML Interview Questions
System Design
Design a CDN (Content Delivery Network)
Design a Content Delivery Network like Cloudflare, Akamai, or AWS CloudFront. A CDN is infrastructure that most large-scale systems depend
System Design
Design a Stock Trading Platform
Design a stock trading platform like NYSE, Nasdaq, or a brokerage like Robinhood. This problem is notable for its extreme
AI/ML Interview Questions
Train/Test/Validation Split: The Right Way and Common Mistakes
Train/test/validation splits are foundational — and routinely misunderstood. The most common mistake in applied ML is using the test set
AI/ML Interview Questions
How to Choose Between Machine Learning Models
One of the most common ML interview questions isn’t about a specific algorithm — it’s “how do you decide which
System Design
Design a Distributed ID Generator (Snowflake)
Design a distributed ID generation service. Every large-scale system needs unique IDs — for database rows, events, messages, and transactions.
System Design
Design Google Maps / Navigation System
Design a navigation system like Google Maps. This problem combines geospatial data at scale, graph algorithms, real-time data ingestion, and
AI/ML Interview Questions
Handling Imbalanced Datasets in Machine Learning
Imbalanced datasets — where one class dramatically outnumbers another — are the norm in production ML, not the exception. Fraud
AI/ML Interview Questions
Feature Selection and Dimensionality Reduction: PCA, Lasso, and Tree Importance
Feature selection and dimensionality reduction are how you fight the curse of dimensionality — the phenomenon where models trained on
System Design
Design a Proximity Service (Yelp / Nearby Search)
Design a proximity service like Yelp’s “restaurants near me” or Google Maps’ nearby search. The core challenge is geospatial indexing
System Design
Design a Hotel / Airbnb Reservation System
Design a hotel or vacation rental reservation system like Booking.com or Airbnb. The core challenge isn’t the search UI —
AI/ML Interview Questions
Cross-Validation Strategies: K-Fold, Time Series, and Nested CV
Cross-validation is how you estimate a model’s generalization performance before deploying it. Getting this wrong — especially data leakage —
System Design
Design a Payment System
Design a payment system like Stripe, PayPal, or an internal payments platform at a company like Uber or Amazon. This
System Design
Design a News Feed (Facebook-style)
Design a news feed system like Facebook’s. This is a richer problem than the Twitter feed design — Facebook’s feed
System Design
Design a Distributed Key-Value Store
Design a distributed key-value store like DynamoDB, Cassandra (its KV layer), or Redis Cluster. This is one of the most