OAuth 2.0 and OpenID Connect by Example with Spring Boot 3
Distinguish OAuth 2.0 from OpenID Connect, build an OIDC login client and JWT-validating resource server with Spring Security, including tests.
Route Handlers: Writing APIs in Next.js
How to use Route Handlers in App Router to write REST APIs: defining methods, reading body, dynamic params, cookies, caching, and testing with Vitest.
Streams in Node.js: processing large files without memory drain
Use Readable, Transform, pipeline, and backpressure in Node.js to read, filter, and compress hundreds of MB files while keeping RAM stable.
useMemo and useCallback in React: When You Really Need Them
Understand what useMemo and useCallback solve, when they reduce unnecessary renders, when they just complicate your code, and how to verify with tests.
Async/Await and Error Handling in Node.js
Learn how async/await works in Node.js, how to catch errors properly with try/catch, and common mistakes when handling Promises.
Building REST APIs with Express in Node.js
A guide to building REST APIs with Express covering routing, middleware, data validation, error handling, and writing tests with Jest and Supertest.
Custom Hooks in React: Extracting Reusable Logic the Right Way
Guide to writing custom hooks to extract stateful logic, avoid code duplication between components, with examples of useFetch, useLocalStorage and how to test.
Data Fetching and Caching in Next.js (App Router)
Learn how Next.js caches fetched data, control revalidation by time or tag, and when to force dynamic rendering.
JWT: Proper Usage and Common Security Mistakes
A comprehensive guide to using JWT safely in Spring Boot and common security issues like alg=none, exposed secrets, and missing expiration checks.
Server Actions: Handle Forms Without a Separate API
Learn Server Actions in Next.js to handle form submission directly from components without writing separate Route Handlers or APIs.
Storing Passwords Correctly: bcrypt and argon2
Learn how to hash passwords securely with bcrypt and argon2 in Spring Boot, avoid common mistakes that leave systems vulnerable to attack.
useState and useEffect: Using Them Correctly
Analyze how useState and useEffect actually work in React, including common mistakes like stale closures, infinite loops, and when not to use useEffect.
5 Ways to Block Prompt Injection: Detailed Explanation with Examples
Learn 5 defensive layers against prompt injection for LLM systems — spotlighting, instruction hierarchy, least-privilege tools, human-in-the-loop, planner/executor split — with example Java code.
App Router in Next.js: Layout, Page and Route
Learn how Next.js App Router organizes routes via page, layout, and route files, with working examples and tests.
CSRF and SameSite Cookie: Defense Mechanisms in Spring Security
Learn how CSRF attacks work, what the SameSite cookie attribute does, and how to configure CSRF tokens correctly in Spring Boot.
Event Loop in Node.js: How It Works and Practical Examples
Explains the Event Loop mechanism in Node.js through phases, with specific code examples about the execution order of setTimeout, Promise, and process.nextTick.
Server Component and Client Component in Next.js
Distinguish between Server Components and Client Components in Next.js App Router, when to use each, and common mistakes when combining both.
SQL Injection and Prepared Statements in Java
Learn how SQL injection works and how PreparedStatement/JPA help you defend against it completely.
XSS: Attacks and Prevention in Spring Boot Applications
Learn XSS attack mechanisms (Reflected, Stored, DOM-based) and effective prevention using encoding, CSP, and Spring Security tools.