Who Uses LLMs? (Themed Edition) ¶

There's this common argument that only those who are bad at coding, or don't care about the craft of it, use AI to code, or are "fooled" into thinking it is useful. This is pretty clearly false. When we categorize the absolute legends of the industry, we see exactly how elite engineering is evolving.

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1. Low-Level Systems & Graphics Engineers ¶

These developers work close to the metal, writing hyper-optimized code where performance, memory safety, and minimal dependencies are paramount.

Salvatore Sanfilippo ¶

Creator of Redis

• Replaced the fast_float C++ library with a pure C implementation in order to make the project more maintainable, removing around 3.5k lines of code on net.
• Wrote a Flux 2 image generation model inference library in pure C with zero external dependencies.
• Wrote a blog post covering some other things he did, and why he is using AI so heavily now: "Don't fall into the anti-AI hype".

Andrej Karpathy ¶

Founding member of OpenAI and former Director of AI at Tesla

• Proclaimed that: "The hottest new programming language is English".
• Uses AI tools like Cursor to build high-performance C code: llm.c.

Andreas Kling ¶

Creator of SerenityOS and Ladybird

• "Agentic coding is the greatest QoL improvement I've ever experienced."
• Fully reimplemented Ladybird's JavaScript engine in Rust, producing byte-for-byte compatible output and seeing no test regressions out of over 60,000 tests, using coding agents.

Sebastian Aaltonen ¶

Industry veteran (Ubisoft internal engines, Unreal Engine 4 optimization, lead of Unity DOTS graphics team)

• "Yes, LLM[s] write BS if you don't manage it properly. But if you provide it clear architecture and task it precisely, it will provide surprisingly good code."

John Carmack ¶

Creator of Doom, Quake, and pioneer of 3D video games

• Has said: "'Coding' was never the source of value, and people shouldn't get overly attached to it. … I suspect that I will enjoy managing AIs more, even if they wind up being better programmers than I am."

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2. Language Creators & Framework Architects ¶

The foundational minds who built the mainstream languages, compilers, package managers, and web frameworks powering the modern internet ecosystem.

Guido van Rossum ¶

Creator of Python

• In an interview with Lex Fridman, said: "You know where that [coding] is going? GitHub CoPilot. I use it every day, and it writes a lot of code for me."

Chris Lattner ¶

Creator of LLVM, Clang, and Swift

• In an interview with Jeremy Howard, said: "It’s amazing for learning a codebase you’re not familiar with, so it’s great for discovery. The automation features of AI are super important. Getting us out of writing boilerplate, getting us out of memorizing APIs, getting us out of looking up that thing from Stack Overflow; I think this is really profound. This is a good use."
• Not an unalloyed booster, though: "Software craftsmanship is the thing that AI code threatens. Not because it’s impossible to use properly—again, I use it, and I feel like I’m doing it well because I care a lot about the quality of the code. But because it encourages folks to not take the craftsmanship, design, and architecture seriously."

Armin Ronacher ¶

Creator of Flask, Pygments, Jinja, and other OSS projects

• Initially was against AI: "I Think AI Would Kill my Wife".
• Now is all-in: "AI Changes Everything", "Welcoming The Next Generation of Programmers", "90%" ("For the infrastructure component I started at my new company, I’m probably north of 90% AI-written code.")

Simon Willison ¶

Co-creator of the Django web framework, board member of the Python Software Foundation, and creator of Datasette

• Writes a lot about using LLMs for various things on his blog: SimonWillison.net

Yehuda Katz ¶

Creator of Handlebars, Ember.js, and Rust's package manager Cargo

• Writes here about his process: "I’ve been using AI code assistants for ages at this point, and I’ve landed on a productive workflow for myself. … I mostly use Windsurf with Cascade for the vibe coding portion. I have a Pro account, and chew through a decent number of tokens. … This is what I do, day in and day out. And it’s made me much more productive."

Ryan Dahl ¶

Creator of Node.js and Deno

• "the era of humans writing code is over."

David Heinemeier Hansson ¶

Creator of Rails and Basecamp

• Wrote a blog post about his use of AI agents, here: "Promoting AI agents"

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3. Toolsmiths, Authors, & Pioneers of "Vibe Coding" ¶

These developers build the environments we work in every day or literally wrote the textbooks on language adoption and system design.

Steve Klabnik ¶

Writer of The Rust Programming Language book, Rust core team member, Ruby on Rails contributor

• Talked extensively about using AI, and how to push back against AI haters, on a podcast with the Zed team, where he also mentioned that he would've considered himself an "AI hater" up until 2025.
• Has now written a prototype systems programming language (a sort of Rust-lite), talking about how Claude Code made it possible ("I have also been wondering for a few years if you can build a language without financial backing and a team. I think LLMs might change that equation. Yes, Claude costs money, but I mean like, you don’t need to do what Mozilla did and drop seven or eight figures worth of money on a development team to make meaningful progress.") and how Claude writes most of his code lately: "But one thing that 2025 changed: I went from an AI skeptic to writing most of my code with Claude."
• Has written a blog post about how the AI discourse in general (not just from the hype side) is bad (generally uninformed and tribalistic).
• Has written about his experiences positive and negative with Claude.
• Has written a few primers and tutorials for agentic development: Agentic development basics, Getting started with Claude for software development, How to think about Gas Town.

Nathan Sobo ¶

Creator of the Zed text editor, team lead on Atom, co-creator of Teletype, contributor to tree-sitter

• His team says coding agents are "a part of their daily workflow."
• Wrote a whole article on how he uses AI to improve craftsmanship.

Mitchell Hashimoto ¶

Creator of Ghostty and Terraform

• Shipped a non-trivial Ghostty feature largely developed by AI.
• My AI Adoption Journey - "I'm also operating under the goal of having an agent running at all times. If an agent isn't running, I ask myself 'is there something an agent could be doing for me right now?'"

Chris Wellons ¶

Creator of Elfeed and many other Emacs packages

• No longer writes code by hand. Explicitly left his previous company because they were behind in adopting AI in order to join a new one that was more AI forward.
• Fun quote: "Everything I said about AI in late 2024 is, as I predicted, utterly obsolete. There’s a huge, growing gap between open weight models and the frontier. Models you can run yourself are toys. In general, almost any AI product or service worth your attention costs money. The free stuff is, at minimum, months behind. Most people only use limited, free services, so there’s a broad unawareness of just how far AI has advanced. AI is now highly skilled at programming, and better than me at almost every programming task, with inhumanly-low defect rates. The remaining issues are mainly steering problems: If AI code doesn’t do what I need, likely the AI writing it didn’t understand what I needed."
• Stopped working on his emacs packages because he is now productive enough thanks to AI to build the GUI versions of the apps he wants instead.

Ricardo Cabello ¶

Creator of JavaScript 3D rendering library Three.js

• "We're at 1.92% [of threejs code being written by AI]. Thanks to AI we now have: 1:1 render parity with Blender's EEVEE, a robust OpenUSD loader, a much improved Collada loader, a much improved threejs editor, Google Chrome devtools, reduced project dev dependencies by 75%, JSDocs based new documentation, made JSDocs 500x faster for all users."

Jarred Sumner ¶

Creator of Bun

• "I expect OSS to go the opposite direction: no human contribution allowed. Slop will be a nostalgic relic of 2025 & 2026."

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4. The Guardians of Architecture, Methodology, & Verification ¶

This category represents the software engineering purists. These individuals focus on engineering rigor, internet-scale systems infrastructure, formal testing, and educational theory.

Andrew Tridgell ¶

Author of Samba, co-creator and primary maintainer of rsync

• Faced with a massive defensive overhaul for rsync—requiring thorough test suites, code coverage, and vulnerability scanning—he "used AI tools to do the grunt work because they are good at that" and "I’m retired and I’d rather be out sailing."
• He specifically targeted AI tools to handle the heavy lifting and grunt work of writing these security defenses, noting that the resulting commits showing code co-authored by Claude are just "the tip of the proverbial software engineering iceberg."
• He emphasizes that knowing exactly how LLMs work doesn't diminish their utility, and flatly dismisses critics who argue that they are just faulty statistical tools, stating, "I do know (well, roughly!) how LLMs work, but that doesn’t make them not useful," and adding that academics who claim the world will fall apart if you use them are simply "out of date. The world of software engineering has changed dramatically in the last few months."

Kent Beck ¶

Creator of Extreme Programming, signatory on the Agile Manifesto, pioneer of Test-Driven Development (TDD), and co-writer of JUnit

• Has written a whole thinkpiece about how the IDE needs to change for a world where humans write very little code anymore, but review much more.

Marc Brooker ¶

VP and Distinguished Engineer at AWS (worked 16 years on EC2, EBS, Lambda, and led the team behind Aurora DSQL)

• Some examples of his opinions: You Are Here, On the success of 'natural language programming'.
• Also has a deep interest in formal specification and verification.

Peter Norvig ¶

Influential educator, author, and AI researcher

• In "Large Language Models and the Future of Programming", says: "I think in the future, programming is going to be thought of more as a collaboration, not as instructions — it's not the programmer telling the computer what to do, it's the two exploring the space together to solve the problem."

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5. Pragmatic Adopters & Nuanced Perspectives ¶

Industry heavyweights who are evaluating AI heavily based on utility, applying it to personal micro-projects, or finding immense defensive value in automated tooling.

Linus Torvalds ¶

Creator of the Linux kernel and the Git version control system

• Wrote a new open-source project called AudioNoise with a small part of it vibe coded in Python ("Also note that the python visualizer tool has been basically written by vibe-coding.").
• Has said that: "There is zero point in talking about AI slop. That's just plain stupid. … It's why I strongly want this to be that 'just a tool' statement."
• Has also called himself "a huge believer in AI as a tool." and said that "[he is excited about using] AI as the tool to help maintain code, including automated patch checking and code review before changes ever reach him."

Martin Kleppmann ¶

Author of Designing Data-Intensive Applications

• Seems pretty enthusiastic about the prospects of vibe coding in conjunction with agentically coding formal specs.

Daniel Stenberg ¶

Creator of curl

• Does not apparently use AI himself, but LLM-based security scanners were able to provide a lot of value for him, and he found them very impressive, despite the ongoing AI slop siege of bug reports in the main curl repo.