No recycled docs, no paraphrased Wikipedia. Every article is written by someone who has actually built the thing — with real diagrams, real trade-offs, and real code.
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Jul 8 — How to Design a URL Shortener Like TinyURL…
Jun 27 — Payment Processing Systems: A Complete Architect’s Guide
Nov 23 — Demystifying What is an IP Addresses: Your Essential…
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8 articles
Architecture breakdowns of real systems — payment processing, distributed databases, rate limiters — explained end to end.
Browse articles4 articles
Full build logs for real applications, from first commit to production, with the decisions and trade-offs included.
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Practical Spring Boot + AI engineering — LLM integration, RAG pipelines, and agents, for working Java developers.
Browse articlesEvery article is written by someone who has actually built the thing. No recycled docs, no paraphrased Wikipedia.
If a junior developer can't follow it, the article isn't ready. No jargon for its own sake.
We don't do 300-word overviews. If a topic is worth covering, we cover it properly — diagrams, examples, code.
A few weeks ago, a friend of mine — three years into his backend career, preparing hard for an SDE role at a company most of us would kill to…
Read the full breakdownPayment Processing Systems: From a user clicking "Buy" to funds settling in a merchant's account —…
An IP address (Internet Protocol Address) is a unique numerical identifier assigned to every device connected…
The OSI (Open Systems Interconnection) Model is a conceptual framework that defines how two systems communicate…
“I started CodeSpy because I was tired of technical content that either oversimplified everything or assumed you already knew it all. This site is what I wish existed when I was learning.”
“Founded CodeSpy in 2022 to make backend engineering and system design genuinely accessible. Leads editorial strategy, writes on Spring AI and distributed systems, and reviews every article before it goes live.”
“Co-founded CodeSpy and drives its System Design content — breaking down complex architectural concepts, from payment processing systems to distributed databases, into articles that are rigorous, practical, and interview-ready.”
A few weeks ago, a friend of mine — three years into his backend career, preparing…
Payment Processing Systems: From a user clicking "Buy" to funds settling in a merchant's account —…
An IP address (Internet Protocol Address) is a unique numerical identifier assigned to every device connected…
The OSI (Open Systems Interconnection) Model is a conceptual framework that defines how two systems communicate…
In modern system design, applications are no longer confined to a single server.Microservices, distributed databases, cloud…
When we talk about great systems whether it’s Netflix streaming billions of hours of video, or…
Introduction - Why Availability Matters Imagine your favourite shopping site goes down during a big sale…
Spring AI Multimodality: As AI technologies advance, the ability to process and generate different types of…
As AI-driven applications evolve, the need to generate and manage structured data becomes increasingly important. Structured…
In the world of AI-driven applications, spring ai function calling is a game-changer that allows you…
In the realm of AI applications, prompts play a crucial role in guiding AI models to…
Spring AI Project: In the rapidly evolving world of technology, integrating AI capabilities into your projects…
In this post, we will delve into how to create a docker image for spring boot…
Online hotel booking system project is a full stack project. Well, you must be aware about…
Bus Ticket Booking System Project In Java SpringBoot And Angular. We have developed this project on…
Hey Folks, In this post, we are going to discuss a project "Airline Reservation System Project…