Konark Lohat’s Post

Day 17. I stopped using @Autowired. Not because it doesn’t work. Because it hides problems. I used to write this: @Autowired private UserService userService; Every tutorial does it. It works. Until you try to test it. Then you realize: → You can’t see dependencies clearly → You need Spring context just to run tests → Your class is tightly coupled That’s when it clicked. The issue isn’t @Autowired. The issue is hidden dependencies. So I switched to this: (see implementation below 👇) Constructor injection. Dependencies are explicit. Your class is honest. Testing becomes simple. The hard truth: → @Autowired works — that’s why everyone uses it → Constructor injection scales — that’s why senior devs prefer it → The difference shows up when your code grows Writing code that runs is easy. Writing code that is testable and maintainable is what makes you a backend developer. Are you still using @Autowired? 👇 Drop it below #SpringBoot #Java #BackendDevelopment #CleanCode #JavaDeveloper

Day 18. I was using @Transactional everywhere. Thinking I was writing safe code. I wasn’t. I was slowing my system down. Every time you add @Transactional, you open a database connection. And you hold it. Until the method finishes. I had it on everything. Read methods. Write methods. All of it. Under load — it broke. Connection pool exhausted. API slowed down. Then stopped responding. That’s when it clicked. @Transactional is not protection. It’s a cost. I had code like this: @Transactional public UserDTO getUser(Long id) { User user = repository.findById(id).orElseThrow(); return new UserDTO(user); } No writes. Still holding a transaction. Completely unnecessary. So I changed it. (see implementation below 👇) What I learned: → Not every method needs a transaction → Read operations usually don’t → Write operations always do The hard truth: → @Transactional is overused → Most developers don’t know why they added it → It only shows under load Adding @Transactional is easy. Knowing when NOT to add it is what makes you a backend developer. Are you using @Transactional everywhere? 👇 Drop it below #SpringBoot #Java #BackendDevelopment #JavaDeveloper #Performance

I pushed broken code to production once. A PR merged without proper review the same week. Two incidents. One lesson. I never ship without a checklist now. Early in my career I thought checklists were for people who did not trust themselves. I was wrong. It was not about trust.  When you are tired, you do not think as clearly as when you wrote the code. Tired devs miss things. The checklist does not miss anything Here's exactly what I run through before pushing any NestJS backend to production: 🔸 Code Quality ☑️ No console.logs left in the codebase ☑️ No hardcoded values, especially credentials ☑️ Dead code removed, not commented out 🔸 Before the PR ☑️ I go through changes line by line before asking for a review. ☑️ My PR description clearly explains what changed and why. ☑️ Each PR focuses on one thing, I do not mix unrelated changes. 🔸 Database ☑️ Migrations tested on staging first ☑️ No migration that can't be rolled back ☑️ No raw queries without input sanitization 🔸 API Layer ☑️ All new endpoints have validation (DTOs in NestJS) ☑️ Error responses are consistent with existing API format ☑️ Auth guards applied, nothing accidentally public 🔸 Before Deployment ☑️ Staging tested with production like data ☑️ Team notified, no surprise deploys ☑️ Rollback plan exists before I push This list was built from mistakes. Real incidents. Real consequences. Most production incidents are not caused by bad developers. They are caused by good developers moving fast without a system. The checklist is the system. Save this. Steal it. Improve it for your own stack. And if you are building a backend right now without one, start today, not after your first incident. DM me BUILD if you want me to review your deployment process. #SoftwareEngineering #NestJS #NodeJS #BackendDevelopment #CleanCode #WebDevelopment #DevOps #CodeReview #ScalableSoftware #ProgrammingTips

🚀 Day 6/45 – Backend Engineering (REST API Design) Today I focused on common mistakes developers make while building APIs. 💡 What I learned: 🔹 Mistake 1: Using wrong HTTP methods GET for updates ❌ POST for everything ❌ 👉 Use proper semantics (GET, POST, PUT, DELETE) 🔹 Mistake 2: Poor endpoint design /getAllUsers ❌ /createUser ❌ 👉 Use clean, resource-based endpoints: /users /users/{id} 🔹 Mistake 3: Ignoring status codes Always returning 200 ❌ 👉 Use: 201 → created 400 → bad request 404 → not found 🔹 Mistake 4: No pagination 👉 Leads to performance issues with large data 🛠 Practical: Refactored APIs in my project to follow REST standards with proper endpoints, status codes, and pagination. 📌 Real-world impact: Well-designed APIs: Improve frontend integration Reduce bugs Scale better in production 🔥 Takeaway: Good APIs are not just functional — they are predictable, scalable, and easy to use. Currently building a production-ready backend system — sharing real learnings daily. https://lnkd.in/gJqEuQQs #Java #SpringBoot #BackendDevelopment #RESTAPI #SoftwareEngineering

🚀 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗲𝗮𝗻 𝗟𝗶𝗳𝗲𝗰𝘆𝗰𝗹𝗲 — 𝗜𝗳 𝗬𝗼𝘂 𝗗𝗼𝗻’𝘁 𝗨𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱 𝗧𝗵𝗶𝘀, 𝗬𝗼𝘂’𝗿𝗲 𝗗𝗲𝗯𝘂𝗴𝗴𝗶𝗻𝗴 𝗕𝗹𝗶𝗻𝗱 Most developers use Spring daily… But can’t answer this: 👉 𝗪𝗵𝗮𝘁 𝗵𝗮𝗽𝗽𝗲𝗻𝘀 𝘁𝗼 𝗮 𝗯𝗲𝗮𝗻 𝗮𝗳𝘁𝗲𝗿 𝗶𝘁’𝘀 𝗰𝗿𝗲𝗮𝘁𝗲𝗱? 🧠 The Lifecycle: Creation → Injection → Initialization → Ready → Destruction That’s it. But each step matters. ⚙️ 𝗞𝗲𝘆 𝗦𝘁𝗮𝗴𝗲𝘀 𝗕𝗲𝗮𝗻 𝗗𝗲𝗳𝗶𝗻𝗶𝘁𝗶𝗼𝗻 𝗟𝗼𝗮𝗱𝗲𝗱: Spring reads the config and decides what beans need to be created 𝗕𝗲𝗮𝗻 𝗜𝗻𝘀𝘁𝗮𝗻𝘁𝗶𝗮𝘁𝗲𝗱: Object is created in memory (constructor runs) 𝗗𝗲𝗽𝗲𝗻𝗱𝗲𝗻𝗰𝗶𝗲𝘀 𝗜𝗻𝗷𝗲𝗰𝘁𝗲𝗱: Required dependencies are wired into the bean 𝗕𝗲𝗮𝗻𝗣𝗼𝘀𝘁𝗣𝗿𝗼𝗰𝗲𝘀𝘀𝗼𝗿 (𝗕𝗲𝗳𝗼𝗿𝗲 𝗜𝗻𝗶𝘁): Custom logic runs before the bean is initialized 𝗜𝗻𝗶𝘁𝗶𝗮𝗹𝗶𝘇𝗮𝘁𝗶𝗼𝗻 (@𝗣𝗼𝘀𝘁𝗖𝗼𝗻𝘀𝘁𝗿𝘂𝗰𝘁 / 𝗶𝗻𝗶𝘁()): Final setup happens — bean becomes fully usable 𝗕𝗲𝗮𝗻𝗣𝗼𝘀𝘁𝗣𝗿𝗼𝗰𝗲𝘀𝘀𝗼𝗿 (𝗔𝗳𝘁𝗲𝗿 𝗜𝗻𝗶𝘁): Bean may be wrapped/modified (e.g., proxies, AOP) 𝗕𝗲𝗮𝗻 𝗥𝗲𝗮𝗱𝘆 𝘁𝗼 𝗨𝘀𝗲: Bean is now used by the application 𝗕𝗲𝗮𝗻 𝗗𝗲𝘀𝘁𝗿𝗼𝘆𝗲𝗱 (@𝗣𝗿𝗲𝗗𝗲𝘀𝘁𝗿𝗼𝘆 / 𝗱𝗲𝘀𝘁𝗿𝗼𝘆()): Cleanup happens — resources are released before shutdown 💣 𝗪𝗵𝗲𝗿𝗲 𝘁𝗵𝗶𝗻𝗴𝘀 𝗯𝗿𝗲𝗮𝗸 ❌ Using bean before initialization → NullPointerException ❌ Ignoring destroy phase → Memory leaks ⚠️ Hard Truth Field injection causes hidden issues Most devs don’t know when init runs Almost nobody handles cleanup properly If you don’t know the lifecycle stage your bean is in… 👉 You’re not debugging 👉 You’re guessing 𝗡𝗲𝘅𝘁 𝘁𝗶𝗺𝗲 𝘆𝗼𝘂𝗿 𝗮𝗽𝗽 𝗳𝗮𝗶𝗹𝘀 — Ask: “Which lifecycle stage broke?” That’s how real backend engineers think. #Java #BackendDeveloper #Hiring #ImmediateJoiner #ServingNoticePeriod #SpringBoot #JavaDeveloper

𝗔𝘀 𝗯𝗮𝗰𝗸𝗲𝗻𝗱 𝗱𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿𝘀, 𝘄𝗲’𝗿𝗲 𝘁𝗮𝘂𝗴𝗵𝘁 𝗲𝗮𝗿𝗹𝘆 𝗼𝗻 𝘁𝗼 𝗮𝘃𝗼𝗶𝗱 𝗡+𝟭 𝗾𝘂𝗲𝗿𝗶𝗲𝘀. And yet… most of us still ship them to production like it’s a feature. Not gonna lie - I’ve shipped it too without realizing. N+1 is simple: 1 query to fetch the list, N more queries for each item. Congrats, you just turned one request into a DB stress test. Everything works fine… until it doesn’t. Slow APIs, spiking DB load, and suddenly your “clean code” is the bottleneck. But sure, blame the ORM - it was just “magically fetching relations,” right? Reality check: the ORM didn’t write bad queries. You did. You don’t really notice it… until your DB starts feeling it. Pay attention to them. They matter more than you think. #BackendDevelopment #JavaDeveloper #SpringBoot #APIDesign #DatabasePerformance #NPlusOne #SoftwareEngineering #CleanCode #PerformanceMatters #DevelopersLife #ScalableSystems #ORM #DevCommunity

A production bug taught me this lesson One small issue. One missing edge case. And suddenly the whole workflow started breaking. At first, I looked at the code. But the real problem wasn’t the code itself. It was: assumptions we made missing logs unclear ownership no retry strategy weak failure handling That day reminded me: The hardest part of engineering is not building the happy path. It’s designing for what happens when things go wrong. Now every feature I build starts with: What can fail? How will I trace it? Who owns it? How does it recover? Real growth as a developer begins when you stop asking “Will this work?” and start asking “How will this fail?” What’s a bug that changed the way you build systems? #SoftwareEngineering #BackendDevelopment #SystemDesign #DeveloperGrowth #ProblemSolving #EngineeringMindset #NodeJS #NestJS #FullStackDevelopment #BuildInPublic

🚀 “Most developers use APIs every day… but very few actually understand how they work.” When I started with Spring Boot, I memorized things like: ✔ @RestController ✔ @GetMapping ✔ @RequestMapping I could build APIs. But if someone asked me: 👉 “What actually happens when a request hits your API?” …I didn’t have a clear answer. That’s when I realized: 👉 I was learning annotations 👉 But not understanding the flow 💡 Here’s the simple truth behind every REST API: It’s just a flow 👇 Client → Request → Mapping → Controller → Response 🧠 Let’s break it down simply: 🔹 @RequestMapping Routes the incoming request to the right method (Think: “Where should this go?”) 🔹 @RestController Handles the request and sends back response (Usually JSON — what frontend actually uses) 🔹 HTTP Methods • GET → Fetch data • POST → Create data • PUT → Update • DELETE → Remove 🔹 @PathVariable Takes value directly from URL Example: /users/101 🔹 @RequestParam Takes input from query Example: /search?keyword=phone ⚡ Why this matters (real world): When things break in production… Nobody cares if you know annotations. 👉 They care if you understand the flow 👉 They care if you can debug the request 👉 They care if you can fix it fast 💥 Big realization: > APIs are not about writing code. They’re about handling communication between systems. 📌 Simple shift that helps a lot: Don’t just ask: “How do I write this API?” Start asking: “Where does this request come from… and where does it go?” Because that’s where real backend thinking begins. 💬 Let’s test this: Can you clearly explain what happens from API request → response? Yes or still learning? 👇 #SpringBoot #Java #BackendDevelopment #RESTAPI #SoftwareEngineering #Developers #Coding #TechCareers #Programming #SystemDesign

A few years ago, a major bug or a server crash would have sent me into a total panic. Today? I just opened the logs and started debugging. In Full Stack development, things will break. It’s not a matter of "if," but "when." The backend might fail under load. A CSS update might wreck the layout on mobile. A database migration might go sideways. But here is the truth: Our growth as developers isn't measured by how many lines of code we write, but by how we react when things go wrong. Errors aren't failures; they are just "runtime lessons." If you aren’t breaking things occasionally, you aren’t pushing your boundaries or exploring new territories. Don't fear the bugs. Own them, fix them, and document the solution. That’s how you go from "writing code" to "building resilient systems." 💻🚀 #FullStackDeveloper #WebDevelopment #CodingLife #SoftwareEngineering #GrowthMindset #DevLife

Day 90 of My 9-Month Coding Challenge 🎯 Error Handling & API Stability in Backend ⚙️ Today, I focused on making my backend more robust by implementing proper error handling—because a secure system is not just about preventing attacks, but also about handling failures gracefully. 🛠️ What I Worked On: ✔ Implemented centralized error handling middleware in Express ✔ Created custom error classes for consistent error responses ✔ Handled async errors using wrapper functions (avoid try-catch repetition) ✔ Managed validation, authentication, and server errors separately ✔ Sent structured error responses (status code + message + details) 📚 Key Learnings: ✅ Unhandled errors can crash your server or expose sensitive data ✅ Centralized error handling improves maintainability ✅ Consistent error responses make APIs easier to debug and consume ✅ Never leak internal error details in production ✅ Proper logging is essential for debugging real-world issues 🧠 Core Concept: Stable Backend = Proper Error Handling + Controlled Responses + Safe Logging 💡 Insight: Users don’t trust systems that fail unpredictably. Handling errors well is just as important as writing correct logic. Still learning. Still improving. Still consistent. 💯 #Day90 #9MonthChallenge #NodeJS #ExpressJS #BackendDevelopment #ErrorHandling #WebDevelopment #MERN #BuildInPublic #Consistency