Dr Code (@oses4sure) header
Dr Code (@oses4sure) profile picture

web developer, App Developer. HTML, CSS, JavaScript, React, React Native, Node js, MongoDB, Postgres, UI/UX Designer

Benin
Joined June 2012
Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)Photo by Dr Code (@oses4sure)
Dr Code retweeted
Backend Developer Roadmap 2026 1. 🟢 JavaScript / TypeScript 2. ⚙️ Node.js + Express.js 3. 🌐 HTTP + REST APIs 4. 🗄️ PostgreSQL + MongoDB 5. 🔐 Authentication + Authorization 6. ⚡ Redis + Caching 7. 📨 Message Queues + Background Jobs 8. 🏗️ System Design + Microservices 9. 🐳 Docker + CI/CD 10. ☁️ Cloud + Production Deployment Learn → Build APIs → Scale → Deploy Save this roadmap. Become a production-ready backend engineer.
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50 System Design Concepts Every Developer Should Understand to Build Better Software Systems ① Scalability → Handling increasing users and workloads. ② Availability → Keeping systems accessible when users need them. ③ Reliability → Ensuring systems work consistently without failures. ④ Fault Tolerance → Keeping systems running when components fail. ⑤ High Availability → Minimizing downtime through redundancy. ⑥ Performance → Making applications respond quickly and efficiently. ⑦ Latency → Measuring how long a request takes. ⑧ Throughput → Measuring how many requests a system handles. ⑨ Load Balancing → Distributing traffic across multiple servers. ⑩ Horizontal Scaling → Adding more servers to handle increased workloads. ⑪ Vertical Scaling → Increasing the resources of an existing server. ⑫ Reverse Proxy → Forwarding client requests to backend servers. ⑬ API Gateway → Managing and routing incoming API requests. ⑭ Caching → Storing frequently accessed data for faster retrieval. ⑮ CDN → Delivering content from geographically distributed servers. ⑯ Database Sharding → Splitting data across multiple database instances. ⑰ Database Replication → Maintaining copies of data across servers. ⑱ Database Indexing → Speeding up database queries. ⑲ SQL vs NoSQL → Understanding relational and non-relational databases. ⑳ Database Partitioning → Dividing large datasets into smaller sections. ㉑ ACID Properties → Ensuring reliable database transactions. ㉒ CAP Theorem → Understanding consistency, availability, and partition tolerance. ㉓ Eventual Consistency → Allowing distributed replicas to synchronize over time. ㉔ Strong Consistency → Ensuring users see the latest committed data. ㉕ Distributed Systems → Coordinating multiple computers to work together. ㉖ Microservices Architecture → Breaking applications into independent services. ㉗ Monolithic Architecture → Building an application as one deployable unit. ㉘ Event-Driven Architecture → Communicating through events and messages. ㉙ Message Queues → Handling asynchronous communication between services. ㉚ Publish-Subscribe Pattern → Distributing messages to interested subscribers. ㉛ Kafka → Streaming and processing real-time event data. ㉜ WebSockets → Enabling real-time, two-way communication. ㉝ REST APIs → Designing resource-based HTTP interfaces. ㉞ GraphQL → Allowing clients to request specific data. ㉟ gRPC → Enabling efficient service-to-service communication. ㊱ Rate Limiting → Controlling how frequently clients can make requests. ㊲ Throttling → Restricting excessive traffic to protect services. ㊳ Circuit Breaker Pattern → Preventing repeated calls to failing services. ㊴ Retry Pattern → Reattempting failed operations safely. ㊵ Idempotency → Ensuring repeated requests don't create unintended effects. ㊶ Service Discovery → Finding available services dynamically. ㊷ Leader Election → Selecting a coordinator in distributed systems. ㊸ Consensus Algorithms → Helping distributed nodes agree on shared decisions. ㊹ Data Replication → Keeping information synchronized across multiple locations. ㊺ Disaster Recovery → Restoring systems after major failures. ㊻ Observability → Understanding system behavior through logs, metrics, and traces. ㊼ Monitoring & Alerting → Detecting problems before they become major incidents. ㊽ Authentication & Authorization → Verifying identities and controlling access. ㊾ Data Encryption → Protecting sensitive information during storage and transmission. ㊿ Backpressure → Preventing overloaded services from overwhelming other components. Don't just memorize these concepts. Understand why they exist, when to use them, and how they interact. That's how you move from writing code to designing systems that scale, survive failures, and serve millions of users. Follow @e_opore for more software engineering and system design content.
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If your React apps feel like they're missing a layer of safety and clarity, this course is for you. In it, Rachel shows you how to refactor a project to be fully type-safe, more readable, and easier to maintain. You'll define component props, handle function props, and catch bugs before they reach the browser, too. freecodecamp.org/news/level-…
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Dark mode toggles usually rely on JavaScript, but they don't have to. In this tutorial, @jcubic explains how to build one with just HTML and CSS. You'll use radio buttons, labels, CSS variables, and more to switch themes while keeping the site usable without JS. freecodecamp.org/news/how-to…
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Database interview question: Your PostgreSQL database is using 95% CPU. Queries look normal. What are you checking first?
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As a software developer, you should know how to work with databases. And if you need to learn the basics or brush up on your skills, this course is for you. It covers client & network layers, execution management, storage engines, indexing, & lots more. freecodecamp.org/news/learn-…
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If you're building a project and eventually hope to bring others on board, you'll want to create a README file. And in this guide, @casweb_dev explains how to structure it effectively. He walks you through all the important info to include, and even shares a template you can use for your own READMEs. freecodecamp.org/news/how-to…
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Interviewed a Senior Backend Engineer today. Knew databases, queues, distributed systems — all of it. Then I asked: You have 50 servers. Each one creates orders. Every order needs a unique ID. No collisions. Ever. Auto-increment does not work. 50 servers, 50 databases. UUIDs work, but they are 128 bits, completely random, and terrible for database indexes. I need IDs that are: → Unique across all servers → Roughly sorted by time → Generated without calling any other server Silence. How would you design it? 👇
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Go GOD LEVEL in SYSTEM DESIGN by learning THESE:
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If you need to brush up your math skills, this collection of courses is for you. It's a list of more than 220 of the top online math courses from the 60 best universities in the world. You can learn about linear algebra, differential equations, vector calculus, statistics and probability, and lots more. freecodecamp.org/news/math-o…
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Object-oriented programming is one of the most widely-used programming paradigms in software development. And in this detailed guide, Lucas shows you how it works in TypeScript. You'll learn key TS language features like objects, classes, & interfaces, then see how they give rise to the four pillars of OOP. freecodecamp.org/news/learn-…
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🚨❌ Serious VAR mistake yesterday in the Chelsea vs. Manchester United match. 📸 Estêvão was NOT offside in the build-up to the hosts' second disallowed goal.
Replying to @Blue_Footy
@FutOffsides we need this checked… surely it wasn’t offside
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🎬 AVATAR: FIRE AND ASH Full Movie🍿 ⭐️ 7.7 📅 Release Year: 2025 👻 Genre: Action 🎥 Country: United States nitter.gq/pusatfilm_id/status/21…
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AI agents are more useful when they can remember, use tools, and run from secure places. In this course, Shawn teaches you how to build a Telegram AI agent with Vercel, Cursor, and Composio. You'll add app integrations, long-term memory, mobile access, and scheduled tasks with Vercel Cron along the way. freecodecamp.org/news/build-…
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Dr Code retweeted
As a Frontend Developer, Please slap yourself if you cannot clearly explain at least 10 of the following : Hydration Partial hydration Islands architecture Streaming SSR Concurrent rendering Time slicing Reconciliation algorithm Fiber architecture Virtual DOM diffing complexity Structural sharing Immutable data patterns Referential equality Memoization pitfalls Stale closure problem Event loop (macro vs microtasks) Task starvation Layout thrashing Critical rendering path Render blocking resources Tree shaking internals Code splitting strategies Dynamic import chunking Module federation Shadow DOM Custom Elements lifecycle Web Components interoperability Web Workers vs Service Workers SharedArrayBuffer Transferable objects OffscreenCanvas WebAssembly integration Browser compositing layers Paint vs composite vs layout GPU acceleration in CSS CSS containment Subpixel rendering IntersectionObserver internals ResizeObserver loop limits MutationObserver cost IndexedDB Service Worker lifecycle traps Cache invalidation strategies Stale-while-revalidate ETag vs Cache-Control HTTP/3 and QUIC Priority hints Preload vs Prefetch vs Preconnect CORS preflight SameSite cookie modes CSRF vs XSS mitigation Content Security Policy (CSP) DOM clobbering Prototype pollution Race conditions in UI state Tearing in concurrent UI Render waterfalls Suspense boundaries Selective hydration Server components Edge rendering Micro-frontend orchestration Finite state modeling Event sourcing in frontend Optimistic UI rollback strategy Offline conflict resolution CRDT basics for collaboration WebRTC Backpressure in streams API AbortController Streaming fetch response handling Browser memory leak detection Detached DOM nodes Garbage collection timing PerformanceObserver API Long tasks API First Input Delay (FID) Interaction to Next Paint (INP) Cumulative Layout Shift (CLS) Largest Contentful Paint (LCP) Speculative prerendering Priority inversion in async code Deterministic rendering
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Getting a web dev job today is more competitive than ever. You need more than just a portfolio to land a job. Here, Ilyas goes over strategy, skills prep, applications, interviews, and more so you make smarter decisions while looking for your next role. freecodecamp.org/news/the-ul…
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A vite: not found error can be the last symptom of a dependency install that failed much earlier. In this article, Ahmed shows you how to trace the failure back and see what actually made it into node_modules. You’ll also learn how to safely rewrite public-package URLs and add checks that stop broken container builds sooner. freecodecamp.org/news/diagno…
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Tutorials on AI agents and tool calling often leave some key questions unanswered. What happens if a tool call fails? How are arguments validated? What tells an agent to stop running? Etc. In this guide, @gkoos430 teaches you all about agent harnesses (and how they help) by building a small one in TypeScript. freecodecamp.org/news/how-to…
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TypeScript is a powerful, statically-typed superset of JavaScript that helps you write safer and more maintainable code. And this course teaches you all the fundamentals so you can start using it in your projects. You'll learn about built-in types, type annotation, arrow functions, union, literal, and nullable types, enums, interfaces, and lots more. freecodecamp.org/news/learn-…
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React is a popular front-end JavaScript framework for building interactive user interfaces. And in this beginner-friendly handbook, @oluwatobiss teaches you all the basics. You'll learn about JSX, components, hooks, rendering, and lots more through many code examples and walkthroughs. freecodecamp.org/news/react-…
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