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.
Fresh off the compiler
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.”
“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.”
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Payment Processing Systems: A Complete Architect’s Guide
System Design
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System Design
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