Hi, I’m Umer Mansoor. I’ve been a CTO, Head of Applied AI, director of engineering, engineering manager and lead engineer at various companies, and these days most of my work is in AI.

CodeAhoy is my personal blog. I started it in 2016 as notes to myself — simplifying something and writing it down in a way another person could understand is still the best way I know to learn it.

With more than 70 blog posts, the site found a bigger audience than I expected. I appreciate all the feedback, emails and tweets I’ve received over the years. I hope you find something useful here. Some of the places the writing has turned up:

Hacker News and Lobsters

• Htop Explained Visually — 346 points
• Experienced Programmers Use Google Frequently — 291 points, 174 comments
• When to Rewrite from Scratch — 240 points, 106 comments
• Across some 40 submissions, posts from here have gathered just over 1,000 points on Hacker News.
• Four posts also did well on Lobsters: Technical Debt Is Soul-Crushing, YAGNI, Cargo Cult and Overengineering, Htop Explained Visually and When to Rewrite from Scratch.

Cited in research

• Service-Level Fault Injection Testing — ACM Symposium on Cloud Computing (SoCC ‘21), Carnegie Mellon. Flask microservices tutorial is the starting point for the paper’s evaluation corpus. (PDF)
• Burnout in software engineering: A systematic mapping study — Information and Software Technology (Elsevier, 2023). Cites my 2021 developer burnout survey as one of two industry data points motivating the study.
• Machine Learning Models for the Early Detection of Burnout in Software Engineering: a Systematic Literature Review (Tulili, Rastogi and Capiluppi, 2026) — the same group cites the survey again.
• Wikipedia — “Primitive data type”: The char Type in Java is Broken.

In courses, handbooks and roadmaps

• Northeastern University, CS 6650 Building Scalable Distributed Systems (Ian Gorton, Khoury College) — Caching Strategies and How to Choose the Right One on the week 7 reading list, next to O’Reilly chapters.
• University of Toronto, CSC309 Programming on the Web — the Winter 2026 lecture slides send students to == vs === in JavaScript.
• roadmap.sh — the Backend roadmap’s Caching topic recommends the same post.
• System Design Interview: An Insider’s Guide (Alex Xu): the caching post as a Chapter 1 reference, alongside Scaling Memcache at Facebook.
• UK Government Digital Service — Effective Code Reviews in the GDS Technology Learning Pathway’s code review resources, filed under “phrasing review comments positively”.
• Submitty, Rensselaer’s open-source autograder, points its contributors to Unit, Integration and End-To-End Tests.
• Full Stack Python: serverless architectures post.

Press, blogs and podcasts

• Hackaday — “did a beautiful job of explaining it graphically… Sure, you could read the man page, but we think this is a lot better.”
• Mattias Geniar on the same graphic: “This deserves a place next to Brendan Gregg’s performance diagrams.”
• Lifehacker Australia built a whole article on the Google/Stack Overflow post.
• C++ Stories (Bartłomiej Filipek) called it “an intriguing article” and wrote a reply.
• DZone used my technical debt survey to make its case for managing tech debt.
• Radio-T #494, the long-running Russian tech podcast, discussed the Google post on air (May 2016).
• Wanqu Daily (湾区日报) featured three 2016 posts, later translated into Chinese by ApacheCN.
• Official Java account shared the post on Garbage Collection in Java
• HN twitter

On curated lists

• Best websites a programmer should visit (76k stars): “Blog on software and human factors. 100% Tested on Humans.”
• test-your-sysadmin-skills (11k stars) lists the htop guide; awesome-software-architecture (11k stars) marks the caching post as a recommended read.
• Around 900 files in more than 600 public GitHub repositories link here.

Disclaimer: the views and opinions on this blog are my own - not my current or past employers’.

You can find me on GitHub.