codespy.orgBackend engineering & system design,
Backend engineering & system design,
without the fluff.
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.
$ codespy latest --limit 3
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…
3 articles found_
What we cover
Three areas. Covered properly.
System Design
8 articles
Architecture breakdowns of real systems — payment processing, distributed databases, rate limiters — explained end to end.
Browse articlesProjects
4 articles
Full build logs for real applications, from first commit to production, with the decisions and trade-offs included.
Browse articlesSpring AI
5 articles
Practical Spring Boot + AI engineering — LLM integration, RAG pipelines, and agents, for working Java developers.
Browse articles
How we work
The principles behind every article
1
Practitioner-first
Every article is written by someone who has actually built the thing. No recycled docs, no paraphrased Wikipedia.
2
Simple language, real examples
If a junior developer can't follow it, the article isn't ready. No jargon for its own sake.
3
Depth over shallow overviews
We don't do 300-word overviews. If a topic is worth covering, we cover it properly — diagrams, examples, code.
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Latest articles
System Design
July 8, 2026
10 min read
How to Design a URL Shortener Like TinyURL — Step-by-Step for System Design Interviews
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…
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Who's behind this
Built by people who've shipped the thing they write about
“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.”
“System Design content — breaking down complex architectural concepts, from payment processing systems to distributed databases, into articles that are rigorous, practical, and interview-ready.”
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Payment Processing Systems: A Complete Architect’s Guide
System Design
System Availability in System Design: A Complete Guide
System Design
#tcp/ip-stack-in-system-design
#osi-model-for-beginners
#osi-model-layers-and-functions
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