Tim VanReenen

My corner of the internet where I share lessons, experiments, and ideas from my work in product, design, and software engineering.

Building a CLI Secret Manager

key is a macOS CLI for any secret you care about - passwords, tokens, OTP codes, whatever you need close to the shell. I built it to keep Unix composability with native macOS unlock, and learned to favor a trust model you can explain and audit.

When NumPy Is Already the Vector Database You Need

I wrote a small Python vector-store module after watching modest workloads get heavy infrastructure — a personal story about how far NumPy can take you, and a lesson in choosing solutions that fit the problem.

I Forked My Window Manager

AeroSpace was almost exactly what I wanted. So I forked it, rebuilt it, and shipped something I actually use every day.

Embeddings — A Mathematical Rosetta Stone for Generative AI

An introduction to how large language models represent meaning using high-dimensional vector space — showing how machines interpret, connect, and generate human-like language in context.

Blog Charter

An opening writeup on the purpose and intent of this blog and what I hope to share over time.