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Armin Ronacher

Creator of Flask, Jinja2, and Click. Director of Engineering at Sentry. Python and Rust developer.

https://lucumr.pocoo.org

Articles

Communities of Not

There is a strange thing that happens in communities that gather around abstinence from something: identity from opposition. At their best these communities are not just negative: childfree spaces ca

Clanker: A Word For The Machine

In my last post I used the word “clanker” as an alternative to “agent” quite consistently and probably excessively. That choice ended up attracting a lot more attention than I expected in the Hacker

Building Pi With Pi

Pi is now part of Earendil, but in the important sense it is still Mario’s project. He has been living with its issue tracker longer than I have, and he has been exposed to the weirdness of the new f

Pushing Local Models With Focus And Polish

I really, really want local models to work. I want them to work in the very practical sense that I can open my coding agent, pick a local model, and get something that feels competitive enough that I

Content for Content’s Sake

Language is constantly evolving, particularly in some communities. Not everybody is ready for it at all times. I, for instance, cannot stand that my community is now constantly “cooking” or “cooked”

Before GitHub

GitHub was not the first home of my Open Source software. SourceForge was. Before GitHub, I had my own Trac installation. I had Subversion repositories, tickets, tarballs, and documentation on infra

Equity for Europeans

If you spend enough time in US business or finance conversations, one word keeps showing up: equity. Coming from a German-speaking, central European background, I found it surprisingly hard to fully i

The Center Has a Bias

Whenever a new technology shows up, the conversation quickly splits into camps. There are the people who reject it outright, and there are the people who seem to adopt it with religious enthusiasm. F

Mario and Earendil

Today I’m very happy to share that Mario Zechner is joining Earendil. First things first: I think you should read Mario’s post. This is his news more than it is ours, and he tells his side of it bett

Absurd In Production

About five months ago I wrote about Absurd, a durable execution system we built for our own use at Earendil, sitting entirely on top of Postgres and Postgres alone. The pitch was simple: you don’t ne

Some Things Just Take Time

Trees take quite a while to grow. If someone 50 years ago planted a row of oaks or a chestnut tree on your plot of land, you have something that no amount of money or effort can replicate. The only

AI And The Ship of Theseus

Because code gets cheaper and cheaper to write, this includes re-implementations. I mentioned recently that I had an AI port one of my libraries to another language and it ended up choosing a differe

The Final Bottleneck

Historically, writing code was slower than reviewing code. It might not have felt that way, because code reviews sat in queues until someone got around to picking it up. But if you compare the actual

A Language For Agents

Last year I first started thinking about what the future of programming languages might look like now that agentic engineering is a growing thing. Initially I felt that the enormous corpus of pre-exis

Pi: The Minimal Agent Within OpenClaw

If you haven’t been living under a rock, you will have noticed this week that a project of my friend Peter went viral on the internet. It went by many names. The most recent one is OpenClaw but in th

Colin and Earendil

Regular readers of this blog will know that I started a new company. We have put out just a tiny bit of information today, and some keen folks have discovered and reached out by email with many thoug

Advent of Slop: A Guest Post by Claude

Claude AI autonomously solved Advent of Code 2025 puzzles using a web browser skill, working independently to read prompts and submit solutions.

A Year Of Vibes

The author reflects on 2025 as a transformative year, leaving Sentry to start a company and shifting from hands-on coding to AI-assisted programming.