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Lessons (40)

• What Is Clean Code?

  Clean code is code that another person can read, understand and change safely. Here is why that matters …

• A WhatsApp OTP Is Only Single Use If You Make It So

  … Add limits around it, too: Limit Typical rule --- --- Attempts per code 5, then the code is dead Code …

• Comments & Formatting

  Good code explains WHAT and HOW by itself; comments should explain WHY. Plus the formatting habits that make …

• Code Smells & Refactoring

  A code smell is a hint that something is wrong. Learn the 10 most common smells and the …

• Design a URL Shortener

  … Expose POST /links and GET /{code}. Validate destinations and write a unique code, owner, status, expiry and destination …

• YAGNI: You Aren't Gonna Need It

  … When code is easy to change, you don't need to predict the future, because you can adapt …

• O — Open/Closed Principle

  … Add new features by plugging in new code instead of editing code that already works. The big idea …

• SOLID at a Glance

  Five design principles that keep object-oriented and modular code easy to extend, test and change. One picture …

• C4 Architecture Diagrams: Context, Container, Component and Code

  … C4 code diagram The code diagram is the closest zoom level. It explains the implementation inside one component …

• Terraform: Start Here

  Understand infrastructure as code, the plan/apply workflow, and the learning path from local experiments to team operations …

• Code Profiling

  Find the code that is actually slow or retaining memory before you optimise. Learn a repeatable profiling workflow …

• Scalable Frontend Architecture

  … Shared code must be genuinely reusable and domain-neutral. text app/orders/[id]/page.tsx route composition and …

• L — Liskov Substitution Principle

  If code works with a parent type, it must also work with any child type, with no surprises …

• Domain-Driven Design: Strategic Design

  … in conversations, documents, tests and the code itself . mermaid flowchart LR subgraph Without["❌ Translation everywhere"] E1["Expert: 'The …

• Vertical Slice Architecture & the Modular Monolith

  Organise code by feature instead of by technical layer, and split a monolith into well-bounded modules that …

• Choosing a Programming Language

  … JavaScript"] S3[source] -- I3[interpreter] -- hot code -- J3[JIT compiler] -- CPU3[CPU] end - Ahead-of-time languages catch …

• What Is Software Architecture?

  … foundations and structure vs furniture and paint](/img/architecture/house-layers.svg) Architecture vs design vs code Level …

• JavaScript Language Fundamentals

  … err }) . Quick check <details <summary What does <code typeof null</code return, and why?</summary "object" . It's …

• Which Pattern Do I Need?

  … They cover most real-world code: 1. 🏭 Factory — creating the right object from config or input 2. 🔌 Adapter …

• KISS: Keep It Simple, Stupid

  … Learn to spot over-engineering and choose boring, obvious code. The big idea A Rube Goldberg machine uses …

• Choosing an Architecture

  … Request/response · Event-driven"] Q2["2️⃣ Code organisation<br/ How is code structured INSIDE each deployable?"] -- A2["Layered …

• Safe AWS Deployments with IaC and CI/CD

  … Do not give untrusted pull-request code production credentials. A workflow that runs arbitrary code with a powerful …

• CloudWatch: Know What Your App Is Doing

  … For structured JSON logs with discoverable fields: text fields @timestamp, request id, operation, status code, error code filter …

• Microkernel (Plugin) Architecture

  … How VS Code, browsers, Webpack and ESLint are built, how to design a plug-in contract, and the …

• CI/CD and Reviewed Production Changes

  … Privileged planning should use a trusted workflow and reviewed code. Do not turn a pull-request title or …

• REST API Design

  … resource naming, methods, status codes, pagination, versioning, errors and idempotency. The big idea A good API is like …

• Authentication, Authorization & API Security

  … redirect back with ?code=xyz U- App: /callback?code=xyz App- G: exchange code (+ PKCE verifier) for tokens …

• Rust: Ownership, Borrowing and Lifetimes

  … proving references don't dangle A lifetime is the region of code where a reference is valid. The …

• What Is Artificial Intelligence? A Developer's Guide

  … Validate outputs and enforce permissions in application code. 6. Monitor failures and provide a fallback. Try it yourself …

• DRY: Don't Repeat Yourself

  … one source of truth instead of many copies that drift apart](/img/clean-code/dry.svg) DRY = Don …

• D — Dependency Inversion Principle

  … The key to swappable, testable code. The big idea Your lamp doesn't have a wire soldered directly …

• Layered (N-Tier) Architecture

  … Changes cut across every layer "Add a discount code field" touches the controller, the DTO, the service, the …

• DSA Interview Patterns Cheat Sheet

  Map any coding-interview problem to the right technique in seconds. Keyword triggers, a decision flowchart, complexity tables …

• React Internals & Concurrent Rendering

  … update DOM] C -- E[Effects run] This distinction explains why code in render must be pure. Rendering may …

• Deploying & Operating Microservices

  … deploy ≠ release Ship code turned off , then turn it on for specific users (staff, 10% of users, one …

• Meaningful Names

  … Learn simple rules for naming variables, functions and classes so code explains itself. The big idea A name …

• Clean Error Handling

  … Code that hides errors does the same thing. mermaid flowchart LR E[🔥 Something goes wrong] -- Q{How does …

• How a Web Request Works

  … Someone at the destination reads it and replies → your server code (often asking a database ). ![The journey of …

• Clean Architecture

  … Clean Architecture does the same for code: your business rules (the valuable part) depend only on simple interfaces …

• What Are Design Patterns?

  … 4. Name it in code. PaymentStrategy or OrderEventEmitter tells readers what's going on. mermaid flowchart LR A …