We Reconnect 10M WebSocket After Server Dies

Our binary restarts in 3 seconds. That number was the problem, not the fix. Here’s why the cold path is the one that kills you.

How Discord Actually Delivers 15 Million Messages a Second on One Cluster

Consistent hashing, gateway sharding, and the Erlang trick most backends copy wrong. The first time I fanned out to 10,000 sockets, my…

I Traced Why One Slow Test Costs You 55 Seconds. It’s the Execution Model, Not the Test.

cargo test runs binaries serially and can only talk to them through an exit code. Nextest's own docs use a 60-second example to show what…

I Reviewed 300 Pull Requests Like a Principal Engineer. Here’s the One Pattern.

The bug class I kept approving was never visible in the diff. Nine of the last eleven incidents I traced started in a PR I had already…

How Japan Just Beat Claude Mythos

A Tokyo lab posted a benchmark that edges out Fable and Mythos. Read the fine print and you’re scoring a phone tree against a brain.

The 5 Habits I’ve Stolen From the Best Engineers I’ve Worked With.

Five engineers, five habits, one career’s worth of trying not to embarrass myself in code review.

I Designed Notion’s Real-Time Sync at Microsoft.

The interview was for a Microsoft principal-engineer role. The question was about Notion. The reframing was about every distributed system…