Master Coding Skills &
System Design.

Master caching patterns — Cache-Aside, Write-Through, rate limiting with Redis, sorted set leaderboards, distributed locks, and stampede prevention.

Master JavaScript design patterns — Module (IIFE), Observer (pub/sub), Proxy for intercept, Strategy for algorithm swapping.

Master sliding window and two pointer patterns — fixed and variable windows, two sum with sorted array, remove duplicates, minimum window substring.

Master SQL views as reusable virtual tables, BEFORE/AFTER triggers for automatic reactions, and scheduled events without cron.

Master PHP cURL and Guzzle — GET/POST requests, authentication headers, concurrent requests, and error handling for external APIs.

Master load balancing — round robin, weighted round robin, least connections, IP hash sticky sessions, and L4 vs L7 load balancers.

Master JavaScript regex — test/match/replace/exec methods, named groups, lookahead/lookbehind, and validation pattern library.

Master backtracking — the framework (choose, explore, unchoose), N-Queens problem, Sudoku solver, generate all subsets and permutations.

Master MySQL JSON columns — INSERT, JSON_EXTRACT, JSON_SET, JSON_ARRAYAGG, and indexing JSON paths via generated columns.