Authoring the modern web: semantic HTML5 markup, responsive CSS3 architectures, modern JavaScript (ES6+), DOM events, React frontend ecosystems, Node.js & Express backends, SQL & NoSQL databases, RESTful APIs, authentication, testing, and cloud DevOps.
Client-server architecture, HTTP vs HTTPS cryptographic handshakes, recursive DNS resolution hierarchy, URLs & request-response lifecycle, browser Critical Rendering Path (CRP), VS Code setup, DevTools, and Git & GitHub.
Document structure, tags/elements/attributes, semantic HTML vs div-soup, headings, lists, links & tabnabbing security, media (img, audio, video), tables, accessible forms, meta tags & SEO, and WCAG/ARIA basics.
The CSS Cascade, specificity calculation, Box Model (content-box vs border-box), Flexbox one-dimensional flow, CSS Grid two-dimensional matrices, positioning schemes, responsive media queries, and keyframe animations.
V8 engine execution, primitive vs reference types, variable scoping (var, let, const), coercion rules, control structures, functions & arrow functions, array higher-order methods, objects, and modern ES6+ syntax.
The Document Object Model (DOM) tree, node traversal, dynamic CRUD manipulation, event propagation (Capturing & Bubbling), high-performance Event Delegation, form validation, and keyboard accessibility.
Lexical scope & closures, prototype chains & prototypal inheritance, the Event Loop (Call Stack, Web APIs, Task Queue, Microtask Queue), Promises, async/await, and error propagation.
Git internals (Blobs, Trees, Commits, SHA-1 DAG), repository initialization, staging vs committing, branch pointers, fast-forward vs three-way merges, resolving merge conflicts, and team collaboration workflows.
Component-driven architecture (Bootstrap 5) vs Utility-first design (Tailwind CSS). The 12-column grid, responsive breakpoints, Tailwind JIT engine, design tokens, theme customization, and mobile-first methodologies.
Declarative UI, Virtual DOM reconciliation (Fiber), functional components, props & state immutability, Hooks (useState, useEffect, custom hooks), React Router SPA navigation, Context API, and production builds.
Node.js event-driven runtime, Libuv threadpool, building HTTP web servers, Express routing, middleware chain architecture, RESTful endpoints, request/response cycle, environment management, and centralized error handling.
Relational database modeling (PostgreSQL/MySQL), ACID guarantees, SQL CRUD queries, INNER/LEFT JOINs, B-Tree indexes, NoSQL document architecture (MongoDB), Mongoose ODM, and embedding vs referencing schema design.
REST architectural constraints, HTTP verbs & idempotency, semantic status codes (2xx/4xx/5xx), Fetch API & Axios interceptors, designing RESTful APIs, Swagger/OpenAPI documentation, and third-party API integration.
Stateful sessions vs stateless JWT tokens, cryptographic password hashing with bcrypt, OAuth 2.0 / OpenID Connect authorization flows, HTTPS encryption, XSS & CSRF defense, input sanitization, and CORS headers.
The Testing Pyramid, Unit Testing with Jest, Integration Testing with Supertest, writing testable code with Dependency Injection, Test-Driven Development (TDD Red-Green-Refactor), Chrome DevTools, and Node.js memory profiling.
Cloud hosting (Vercel, Netlify, Render, Heroku, AWS), deploying static SPAs with rewrite fallbacks, containerized full-stack apps with multi-stage Dockerfiles, GitHub Actions CI/CD pipelines, DNS/SSL handshakes, and production observability.