Armin Ronacher
Creator of Flask and Jinja. Writes about software at lucumr.pocoo.org.
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Where they publish
lucumr.pocoo.orgBlog Their blog: engineering, open source, and lately AI tooling.
Long technical posts on programming languages, open-source maintenance and, recently, coding agents. Has an Atom feed.
Recent
- Anger, Anxiety and Agency 24 Aug 2026
- Fast and Hard Code 22 Aug 2026
- What Is Reasoning 19 Aug 2026
Show 7 more
- Codeberg Divides 24 Jul 2026
- The Tower Keeps Rising 13 Jul 2026
- Better Models: Worse Tools 4 Jul 2026
- The Coming Loop 23 Jun 2026
- Dangerous Technology For Americans Only 13 Jun 2026
- Gaslighting Openness 10 Jun 2026
- Communities of Not 6 Jun 2026
Link verified 1 Sept 2026. Recent items update automatically from the channel.
@mitsuhikox.com Where posts get announced and argued.
Shorter takes on the same engineering beat, and the place a blog post's argument usually gets tested first.
Recent
- I know these are fictitious internet points but it's still nice! https://t.co/xcZmBDdrwT 1 Sept 2026
- In which I learned that librespot is basically being killed by Spotify. Man entshittification strikes again. 1 Sept 2026
- Ability to introspect and self awareness continues to just be such a cool feature of modern agentic systems. https://t.co/VHnjISPvlJ 1 Sept 2026
Show 17 more
- What should Pi's approach be with regards to server side compaction? 31 Aug 2026
- RT @dhh: Omacom Foundation has raised another $2 million from @xdanger and @brian_armstrong for now a combined TWELVE MILLION DOLLARS from… 31 Aug 2026
- Fun fact: at one point Rust had a lot of Rubyists working on it that heavy influenced the language. I remember doing a talk on it. Attached screenshot is how w… 31 Aug 2026
- While doing actual productive work I have an agent trying to adjusting a firmware for my carplay adapter. Every once in a while the agent asks me to replug the… 31 Aug 2026
- The current escalations in Ukraine make me quite pessimistic of what will unfold over the winter. Kyiv is under constant bombardment with civilian casualties a… 31 Aug 2026
- Did you know what those toys are recycling/reuse schemes for old tape measures? https://t.co/7UQQjTa5a2 30 Aug 2026
- A German saying is "Gut Ding will Weile haben". You can have your agent explain what it means, but that's basically our mantra for getting the Pi refactor righ… 30 Aug 2026
- I currently have a little data scraping project going for the war in Ukraine. At no point in time did I tell the agent *how* to do something, but at one point… 30 Aug 2026
- The cool thing about cheap Chinese hardware: typically very hackable. Bad thing: the same product has like 20 different versions and good luck buying a specifi… 30 Aug 2026
- I really hope that at least a small percentage of Omarchy haters puts their energy towards building competition to Omarchy! 30 Aug 2026
- I feel like the model does not trust me. https://t.co/cmcgxAyQuh 30 Aug 2026
- OpenClaw looks quite a bit different than what you might remember from … checks clock … 5 AI years ago. https://t.co/f72IlrDQuR 30 Aug 2026
- I feel like there could have been a world where e-scooters would have been smaller, less powerful and become a great multi modality vehicle for cities you can… 30 Aug 2026
- Is ShadowRealm dead? https://t.co/g0RiREPvJn 29 Aug 2026
- Sounds about right that review. https://t.co/QjH0KwHeht 29 Aug 2026
- JavaScript needs pub(crate) 29 Aug 2026
- RT @patrickc: Met a German founder this week and asked him if all the stories one reads about the challenges of startups in Germany are exa… 29 Aug 2026
Link verified 1 Sept 2026. Recent items update automatically from the channel.
mitsuhikoGitHub Flask, Jinja, and several hundred repos since.
The code: Flask and Jinja among the best known, plus a long tail of Rust and Python tooling. The account is the record of a long open-source career.
Recent
- agent-stuff — These are commands I use with agents, mostly Claude 1 Sept 2026
- minijinja — MiniJinja is a powerful but minimal dependency template engine for Rust compatible with Jinja/Jinja2 31 Aug 2026
- procspawn — like thread::spawn but for processes 30 Aug 2026
Show 14 more
- catplay-v821-fel-flow 30 Aug 2026
- lucumr — My personal website 30 Aug 2026
- similar — A high level diffing library for rust based on diffs 29 Aug 2026
- pi-drinking-game — Oh well … 28 Aug 2026
- insta-website — Website repo for insta 18 Aug 2026
- insta — A snapshot testing library for rust 17 Aug 2026
- pi-ds4 — Run deepseek4 locally on metal right from within Pi 7 Aug 2026
- fstrings-wtf — Do you understand f-strings? 6 Aug 2026
- dark 20 Jul 2026
- zine — A blog 14 Jul 2026
- talks — Talks I gave over the years as PDF. 13 Jul 2026
- insta-cmd — CLI extension to insta 14 Jun 2026
- ronacher.eu — Just a website 13 Jun 2026
- amazon-how-much — Estimate Austrian parcel tax from the last 365 days of amazon.de deliveries 11 May 2026
Link verified 1 Sept 2026. Recent items update automatically from the channel.
On record
What they believeKorents 5 beliefs, 1 changed mind — each backed by an exact quote.
Compiled by korents.com, not by them: the one-line wordings are korents', the quotes are theirs.
Recent
Omarchy could reasonably switch its packaging system to Nix.
A nix based Omarchy would be amazing. Want to see this!
@mitsuhiko on X Said 29 Aug 2026
Newer model releases have got worse at producing text that is actually pleasant to read and understand.
Maybe I just read too much AI text now vs before, but I really feel like the model's ability to produce text I actually want to read and understand went downhill with newer releases.
@mitsuhiko on X Said 25 Aug 2026
Self-driving cars will not fix commuting; the US needs public transportation instead.
if I was stuck in this traffic every day in a car, I would go insane. No amount of self driving would change that. We need ACs, but the US badly needs to warm up to public transportation.
@mitsuhiko on X Said 19 Aug 2026
Show 2 more
Delegating coding to an agent does not make you program faster, but it gives back roughly 30% of your day because the machine works while you do something else.
Do I program any faster? Not really. But it feels like I’ve gained 30% more time in my day because the machine is doing the work.
AI Changes Everything Said 4 Jun 2025
We do not control neural networks well enough to guarantee an AI will not harm humans, so we should be careful about what capabilities we give them.
The biggest issue is probably that we don’t control neutral networks enough to be able to ensure AI doesn’t harm humans. We can’t even control AI to not reveal internal prompts.
I Think AI Would Kill my Wife Said 17 Feb 2023
Beliefs others hold too
Omarchy could reasonably switch its packaging system to Nix. 2 hold this
A nix based Omarchy would be amazing. Want to see this!
@mitsuhiko on X Said 29 Aug 2026
Latest
Everything, newest firstFeed Posts, videos, repos and beliefs from every card above, in one stream.
Filter & sortAll sources · condensed
- I know these are fictitious internet points but it's still nice! https://t.co/xcZmBDdrwT 1 Sept
- In which I learned that librespot is basically being killed by Spotify. Man entshittification strikes again. 1 Sept
- Ability to introspect and self awareness continues to just be such a cool feature of modern agentic systems. https://t.co/VHnjISPvlJ 1 Sept
- agent-stuff — These are commands I use with agents, mostly Claude 1 Sept
- What should Pi's approach be with regards to server side compaction? 31 Aug
- minijinja — MiniJinja is a powerful but minimal dependency template engine for Rust compatible with Jinja/Jinja2 31 Aug
Show 39 more
- RT @dhh: Omacom Foundation has raised another $2 million from @xdanger and @brian_armstrong for now a combined TWELVE MILLION DOLLARS from… 31 Aug
- Fun fact: at one point Rust had a lot of Rubyists working on it that heavy influenced the language. I remember doing a talk on it. Attached screenshot is how w… 31 Aug
- While doing actual productive work I have an agent trying to adjusting a firmware for my carplay adapter. Every once in a while the agent asks me to replug the… 31 Aug
- The current escalations in Ukraine make me quite pessimistic of what will unfold over the winter. Kyiv is under constant bombardment with civilian casualties a… 31 Aug
- procspawn — like thread::spawn but for processes 30 Aug
- catplay-v821-fel-flow 30 Aug
- Did you know what those toys are recycling/reuse schemes for old tape measures? https://t.co/7UQQjTa5a2 30 Aug
- A German saying is "Gut Ding will Weile haben". You can have your agent explain what it means, but that's basically our mantra for getting the Pi refactor righ… 30 Aug
- I currently have a little data scraping project going for the war in Ukraine. At no point in time did I tell the agent *how* to do something, but at one point… 30 Aug
- The cool thing about cheap Chinese hardware: typically very hackable. Bad thing: the same product has like 20 different versions and good luck buying a specifi… 30 Aug
- I really hope that at least a small percentage of Omarchy haters puts their energy towards building competition to Omarchy! 30 Aug
- I feel like the model does not trust me. https://t.co/cmcgxAyQuh 30 Aug
- lucumr — My personal website 30 Aug
- OpenClaw looks quite a bit different than what you might remember from … checks clock … 5 AI years ago. https://t.co/f72IlrDQuR 30 Aug
- similar — A high level diffing library for rust based on diffs 29 Aug
- Omarchy could reasonably switch its packaging system to Nix. 29 Aug
- pi-drinking-game — Oh well … 28 Aug
- Newer model releases have got worse at producing text that is actually pleasant to read and understand. 25 Aug
- Anger, Anxiety and Agency 24 Aug
- Fast and Hard Code 22 Aug
- Self-driving cars will not fix commuting; the US needs public transportation instead. 19 Aug
- What Is Reasoning 19 Aug
- insta-website — Website repo for insta 18 Aug
- insta — A snapshot testing library for rust 17 Aug
- pi-ds4 — Run deepseek4 locally on metal right from within Pi 7 Aug
- fstrings-wtf — Do you understand f-strings? 6 Aug
- Codeberg Divides 24 Jul
- dark 20 Jul
- zine — A blog 14 Jul
- talks — Talks I gave over the years as PDF. 13 Jul
- The Tower Keeps Rising 13 Jul
- Better Models: Worse Tools 4 Jul
- The Coming Loop 23 Jun
- insta-cmd — CLI extension to insta 14 Jun
- Dangerous Technology For Americans Only 13 Jun
- Gaslighting Openness 10 Jun
- Communities of Not 6 Jun
- Delegating coding to an agent does not make you program faster, but it gives back roughly 30% of your day because the machine works while you do something else. 4 Jun 2025
- We do not control neural networks well enough to guarantee an AI will not harm humans, so we should be careful about what capabilities we give them. 17 Feb 2023