// codespy.org — practitioner-first engineering contentBackend 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 18 — Designing TikTok : A System Design Guide for…
Jul 8 — How to Design a URL Shortener Like TinyURL…
Jun 27 — Payment Processing Systems: A Complete Architect’s Guide
3 articles found_
What we cover
Three areas. Covered properly.
System Design
9 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 18, 2026
18 min read
Designing TikTok : A System Design Guide for SDE3 & Staff Software Engineer Interviews
Designing TikTok : A System Design Guide. "TikTok isn't just a video streaming application. It's one of the world's largest recommendation engines disguised as a social media app." If you've…
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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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