Master Coding Skills &
System Design.

Master SQL window functions — ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD with PARTITION BY. The most asked advanced SQL topic in data and backend interviews.

Master Python decorators — how they work, functools.wraps, decorators with arguments, class-based decorators, and practical examples like memoize and rate limiter.

Learn Composer from scratch — installing packages, PSR-4 autoloading, version constraints, and composer.lock for reproducible builds.

Design a real-time chat system for 500 million users — WebSockets vs polling, Kafka message queue, Cassandra storage, presence service and push notifications.

Master JavaScript array methods — map, filter, reduce, find, every, some, flat, flatMap with real-world examples and interview patterns.

Learn how PHP sessions and cookies work under the hood, how to configure them securely, prevent session fixation and hijacking attacks.

Master stack and queue data structures — LIFO vs FIFO, Python implementation, balanced parentheses, MinStack, and BFS with deque.

Master PHP array functions — array_map, filter, reduce, usort, array_walk and more with real code examples and interview tips.

Build CI/CD with GitHub Actions — test on every push, deploy on merge to main, matrix testing, secrets management, and SSH deploy.