Developer Blog | Toolliyo — Tutorials, Career & Tech

System Design Series : Rate Limiting Explained Simply

System Design Series — Part 31 Imagine you've built a successful e-commerce application. Everything works perfectly. One day, your API suddenly receives 2 million requests in just a few minutes. Some requests come from real users.

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Technology 6m read

System Design Series : Session Management Explained Simply

System Design Series — Part 30 Imagine you log in to your internet banking application. You enter your username and password only once. After logging in, you can: Check your account balance Transfer money Download statements Pay bills You never enter your password again until you log out. But here's the question:

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Technology 6m read

System Design Series: OAuth 2.0 Explained Simply

System Design Series — Part 29 Have you ever clicked one of these buttons? Continue with Google Sign in with GitHub Login with Microsoft You didn't create a new password.

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Technology 7m read

System Design Series: JWT Authentication Explained Simply

How does the server know it's still you? Does the server remember every logged-in user? Not usually. Instead, most modern applications use something called a JWT (JSON Web Token). JWT is one of the most widely used authentication mechanisms in modern web applications, mobile apps, APIs, and microservices.

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Technology 6m read

System Design Series: Authentication vs Authorization Explained Simply

One of the most common interview questions is: "What's the difference between Authentication and Authorization?" Surprisingly, many developers use these terms interchangeably. But they are not the same thing.

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Technology 6m read

System Design Series: gRPC Explained Simply

System Design Series — Part 26 Imagine you're building an online food delivery platform like Swiggy or Zomato. A customer places an order. Behind the scenes, multiple services need to communicate: Order Service Payment Service Restaurant Service Delivery Service Notification Service

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Technology 7m read

GraphQL Explained Simply

System Design Series — Part 25 Imagine you're building an e-commerce application. The homepage needs to display: Product name Price Product image Average rating Seller name

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Technology 6m read

Caching Explained Simply : System Design Series — Part 11

A few years ago, I worked on a project where a single database query took around 300 milliseconds. That doesn't sound bad. Until you realize: 10,000 users were executing the same query repeatedly. The database CPU started increasing.

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Technology 5m read

Redis Caching Patterns for High-Traffic ASP.NET Core Applications

Cache-aside, read-through, write-through, and stampede protection for ASP.NET Core at scale: StackExchange.Redis, IDistributedCache, TTL strategy, and invalidation that survives enrollment spikes.

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Technology 6m read

Next.js vs React SPA for SaaS and LMS Products in 2025

Choosing between Next.js App Router and a classic React SPA for SaaS and learning platforms: SEO, auth boundaries, deployment cost, and when hybrid rendering beats client-only routing.

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Technology 5m read

Semantic Kernel vs LangChain for .NET AI Apps: Real Project Comparison

Semantic Kernel vs LangChain for .NET AI apps: we compared both on a fintech API doc assistant and LMS Q&A bot—DI integration, plugins, observability, and which framework fits production C# teams.

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Technology 4m read