Designing Scalable APIs with Effective Pagination

Topic: Pagination in APIs Returning all data at once is one of the fastest ways to slow down your system. In real-world applications, datasets can be huge. Without pagination, APIs may: • Return massive payloads • Increase response time • Overload servers • Impact user experience Pagination helps by: • Limiting data per request • Improving performance • Reducing memory usage • Making APIs more scalable Common approaches: • Offset-based pagination • Cursor-based pagination Good API design always considers how data will grow over time. Because what works for 100 records won’t work for 1 million. How do you handle pagination in your APIs? #API #BackendDevelopment #Microservices #Java #SystemDesign

Yesterday I shared about Interceptors. Today, taking it a step deeper with AOP in Spring Boot. In my experience while Interceptors work at the request level, AOP works at the method level — perfect for handling logging, performance tracking,  security and transaction management without touching business logic. Why AOP? Keeps your code clean and modular Centralizes concerns like logging, metrics, auth checks Reduces repetitive boilerplate code across multiple services Example: Logging every method execution: @Aspect @Component public class LoggingAspect {    @Before("execution(* com.example.service.*.*(..))")    public void logBefore(JoinPoint joinPoint) {        System.out.println("Executing method: " + joinPoint.getSignature().getName());    } } This ensures that all service methods are automatically logged — no repetitive code in each method. In microservices, combining AOP with Interceptors and Spring Boot’s features can dramatically improve observability and maintainability. 💡 Tip: Use AOP for performance monitoring, security checks, and auditing. #Java #SpringBoot #AOP #Microservices #CleanCode #BackendDevelopment #SoftwareEngineering

Why is your Spring Boot application slow? It’s rarely because of the framework. Most performance issues come from how resources are used. Here are practical techniques that actually make a difference when optimizing a Spring Boot application: 1. Reduce blocking operations Slow database calls or external APIs hold threads and limit throughput. Optimize queries and avoid unnecessary waits. 2. Use connection pooling effectively Database connections are expensive. Instead of creating a new connection for every request, applications use a connection pool. Connections are reused, which improves performance and scalability. 3. Tune thread pools Default settings are not always optimal. Adjust server thread counts based on CPU and request patterns. 4. Add caching where appropriate Repeated database calls can be avoided using caching (e.g., in-memory or Redis). 5. Optimize database queries Use indexing, avoid N+1 queries, and monitor slow queries. 6. Use asynchronous processing Offload non-critical work using async methods or background jobs. 7. Monitor before optimizing Use tools (Actuator, logs, profiling) to identify real bottlenecks before making changes. Key takeaway: Performance is not about making everything faster. It’s about removing bottlenecks and using resources efficiently. #Java #SpringBoot #BackendDevelopment #Performance #SoftwareEngineering

🚀 Understanding Spring Security with JWT Authentication (Complete Flow) Just built and visualized the complete authentication & authorization flow using Spring Boot + Spring Security + JWT 🔐 📌 Key Highlights from the Architecture: ✔️ Client sends login request → /api/auth/login ✔️ Authentication handled via Authentication Manager ✔️ Credentials verified using DAO Authentication Provider ✔️ User fetched from DB using UserDetailsService ✔️ On success → JWT Token generated (with roles & user info) ✔️ Token sent back to client 🔁 For every next request: ➡️ Client sends JWT in Authorization Header ➡️ JWT Filter validates token ➡️ SecurityContext is set ➡️ Role-based access control using @PreAuthorize ❌ Invalid token → 403 Forbidden ✅ Valid token → 200 OK 💡 This setup ensures: Stateless authentication Secure APIs Role-based access control (ADMIN, USER, etc.) 🔥 Currently working on building a full-stack system around this (like Airbnb-style backend). #SpringBoot #Java #BackendDevelopment #JWT #SpringSecurity #RESTAPI #FullStackDeveloper #LearningInPublic #TechJourney

Managing user sessions in microservices can get complex. Instead of storing sessions on the server, JWT (JSON Web Token) makes authentication stateless and scalable by embedding user info and a signature directly into the token. To use JWT effectively:   1. Keep access tokens short-lived (e.g., 30 minutes)   2. Use refresh tokens for longer sessions (e.g., 24 hours)   3. Always store tokens securely on the client side In my application, I’ve configured the access token to expire after 30 minutes and the refresh token after 24 hours. Both are generated using generateAccessToken and generateRefreshToken methods in jwtUtil, and the backend response includes these two tokens for the client to use. In this short video, I break down: JWT structure (Header, Payload, Signature) JWT lifecycle (Login → Token issued → Verified → Access granted) Access vs Refresh tokens with a practical example Best practices for secure, scalable authentication How do you handle JWT expiration and refresh in your projects? #BackendDevelopment #Java #SpringBoot #Microservices #JWT

Upgrades take time. Performance issues don’t wait. Not everything in production is “latest version” — and that’s okay. Most enterprise systems are still running on Spring Boot 2, quietly handling real traffic every day. So it didn’t make sense for Query Guard to support only newer versions. 🚀 Query Guard now supports Spring Boot 2 (legacy systems) - Same plug-and-play setup. - Same query detection. - Now works seamlessly with your existing applications. - No upgrades. No migration headaches. Just better visibility into what your database is really doing. 🔗 Maven Central (Spring Boot 2 compatible version): https://lnkd.in/gkqQBe3j #SpringBoot #Java #Backend #Performance #OpenSource #QueryGuard #SpringBootStarter #PoojithaIrosha #Microservices #JPA #DevTools #Hibernate #SpringBoot2 #DatabasePerformance

🚀 Sync vs Async APIs in Microservices In microservices, one common question is: Should I use Sync or Async API? Here’s a simple way to think about it 👇 🔹 Use Sync API when: -->You need an instant response -->Work is quick and simple Example: Login, fetching user data 🔹 Use Async API when: -->Work takes more time -->You don’t need an immediate response Example: Order processing, sending emails 🧠 Easy Understanding: Sync = Wait and get response now Async = Request now, response later 📌 Simple Rule: Start with Sync → Move to Async when system grows 💡 Good systems use both together #Microservices #SystemDesign #Backend #Java #SpringBoot #APIDesign

Most developers learn JWT as “just a token”. But the real power of JWT is this: It is stateless. That single design choice changes everything in distributed systems. In traditional session-based authentication: → User logs in → Server stores session in memory → Every request checks server memory This works fine on 1 server. But what happens when traffic grows and you scale to 10 servers? Now every server needs access to the same session. This creates major problems: ❌ Memory overhead on every node ❌ Session synchronization complexity ❌ Load balancer stickiness dependency ❌ Horizontal scaling issues JWT solves this beautifully. The server does not store session state. Instead, all required user information is sent inside the token itself. Every request carries its own identity. That means: ✅ Lower server memory usage ✅ Better scalability ✅ Easier load balancing ✅ Perfect for microservices This is why modern scalable systems prefer JWT. Stateless design = scalable design. #BackendDevelopment #Java #SpringBoot #JWT #SystemDesign #Microservices #SoftwareEngineering #Java #SpringBoot #JWT #SystemDesign #BackendDevelopment #SoftwareEngineering #Microservices #CloudArchitecture #Developers #LearningInPublic #TechCareers #ScalableSystems

Unlock the full potential of your Spring applications this spring! Virtual threads are here to revolutionize concurrency, allowing millions of I/O-bound requests without blocking. Discover how to harness this power with Spring Boot 3.2, just a single property away. Read the full article to learn more: https://lnkd.in/gQKvdECS #concurrency #Java #Java21 #Performance #SpringBoot

 Spring Boot 3 Http Interfaces + Security = less boilerplate, more “it just works” energy. If your HTTP clients still feel like they were assembled during a caffeine outage, this one’s for you. In this video: Spring Boot 3 Http Interfaces Security   https://lnkd.in/eezjkkQs Clean APIs, secure calls, fewer opportunities to invent your own distributed-system horror story. #SpringBoot #Java #Backend #SoftwareDevelopment #Security #WebDevelopment #DeveloperTools