Untangling Tokio and Rayon in production: From 2s latency spikes to 94ms flat Learn how we discovered a big performance bottleneck in the Feature Flags service and made Tokio and Rayon play nice with each other.

Great post by my colleague about the work we did to reduce latency spikes in our feature flags service built with rust, Tokyo, and rayon: posthog.com/blog/untangl...

Congrats!

Resolve Merge Conflicts the Easy Way Merge conflicts don’t have to ruin your day. I use mergiraf for structural merging and a Claude Code skill for everything else. Here’s how to set it up.

Resolving gnarly merge conflicts can be a real tedious chore, until now. Grab a structural semantic merge tool, sprinkle a little AI on it, and you're going to have a lot less headaches.
haacked.com/archive/2026...

Credit where credit is due, the new Slack AI bot has been a game changer for finding old slack conversations. I was skeptical, but it actually works for me.

My colleague @dmarticus wrote a great piece challenging the “AI wipes out white-collar jobs in 18 months” narrative.

Software development isn’t typing code. It’s ambiguity, constraints, and coordination. That makes it much harder to fully automate:

dylanamartin.com/2026/02/21/c...

My shirt keeps telling me I’m absolutely right.

One Year at PostHog Reflections on my first year at PostHog.

Blogged: One year at PostHog haacked.com/archive/2026...

I know it's just a stochastic parrot, but sometimes Claude can be wryly dismissive:

tree-me: Because git worktrees shouldn’t be a chore Working on multiple branches simultaneously? I built tree-me to manage git worktrees without the ceremony. Convention over configuration for the win.

Blogged: Don't sleep on git worktrees like I did. But using them can be a bit of a chore. But here's a script that makes using git worktrees a breeze:

haacked.com/archive/2025...

The SDK Doctor will see you now | Changelog S1E3 YouTube video by PostHog

One more reason I love working at PostHog. Our changelog videos are legit hilarious and entertaining!

www.youtube.com/watch?v=xCrf...

My team is hiring a backend focused engineer: posthog.com/careers/back...

Going to see DJ Snake at Drumsheds in London Oct 10!

Spelungit: When git log --grep isn’t enough Ever tried to remember why you made a change six months ago? I built Spelungit so you can search Git commit history with natural language instead of praying to the regex gods.

Check out spelungit: An MCP server I wrote for semantic search of git history. Fully local using a local LLM and sqlite to store embeddings.
haacked.com/archive/2025...

Plans to use stronger online models in the future, but for now, this works pretty well!

Four things in four years at PostHog Four things I've learned in four years at PostHog

Great post from a colleague: four things in four years at PostHog. Lessons useful at any company: pauldambra.dev/2025/09/four...

At every point in the universe, if you look out into space, the universe is expanding in all directions from that point. Every point in the universe is the center of the universe. So ma’am, in answer to your question if I think the world revolves around me, the universe does.

I think GitHub's CodeQL scanning is broken. It looks like every successive warning includes all the previous warnings.

I think I broke Claude. This video is not sped up.

I was trying to find an old router in my order history on Amazon and how did I order this before I was born?!

GitHub - github/scripts-to-rule-them-all: Set of boilerplate scripts describing the normalized script pattern that GitHub uses in its projects. Set of boilerplate scripts describing the normalized script pattern that GitHub uses in its projects. - github/scripts-to-rule-them-all

I recently adapted GitHub's scripts to rule them all github.com/github/scrip... to PostHog's existing bin scripts. Now it's a part of our handbook: posthog.com/handbook/eng...
And there's a repo: github.com/PostHog/scri.... I love the cross-pollination that happens when companies are transparent.

Hey! Looks like I’m an MVP for another year. Much appreciated!

It’s clouds all the way down

major GCP outage is affecting so much downstream

Great demo @damianedwards.com!!!

I broke the AI again. Clearly Cursor is a fan of LISP.

TIL a fact that’s obvious to any French speaking person but wasn’t to me. If it’s not a crescent shape then it’s not a croissant because croissant is literally crescent in French. It might be a viennoiserie instead.

I’ll be speaking at Techorama. Let me know if you’ll be there!

Screenshot of bug report called: The group chat includes people that were never invited

New bug report opened in the TM SGNL github repo github.com/micahflee/TM...

I heard a scenario: Would you rather receive $1M dollars, or a penny on the 1st such that every penny doubles every calendar day.

Of course I pick $1M dollars. What'm I to do with 1 billion pennies? That wouldn't fit in my apt. It'd weigh over 2750 tons! I don't want that headache.

This is a test of skeeting using code.

Cleaning up gone branches A git alias to clean up gone branches. Even ones that have been squashed and merged.

Do you work on a repo that squash and merges PRs? Notice that `git branch --merged` doesn't work in that scenario? Want a git alias that can clean up merged branches even if they've been squashed? Well I got you! An update to my GitHub Flow aliases: haacked.com/archive/2025...