Build to Last

# fast.ai - Build to Last

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# Build to Last

Chris Lattner on software craftsmanship and AI

advice

technical

Author

Jeremy Howard

Published

October 30, 2025

## On this page

* [Talking with Chris Lattner](https://www.fast.ai/posts/2025-10-30-build-to-last.html#talking-with-chris-lattner)
* [Design from First Principles](https://www.fast.ai/posts/2025-10-30-build-to-last.html#design-from-first-principles)
* [Craftsmanship and architecture](https://www.fast.ai/posts/2025-10-30-build-to-last.html#craftsmanship-and-architecture)
* [Dogfooding](https://www.fast.ai/posts/2025-10-30-build-to-last.html#dogfooding)
* [AI, craftsmanship, and learning](https://www.fast.ai/posts/2025-10-30-build-to-last.html#ai-craftsmanship-and-learning)
* [Software craftsmanship with AI](https://www.fast.ai/posts/2025-10-30-build-to-last.html#software-craftsmanship-with-ai)
* [How do we do something meaningful?](https://www.fast.ai/posts/2025-10-30-build-to-last.html#how-do-we-do-something-meaningful)

> Note from Jeremy: We’re teaching a course starting Nov 3rd on how to build towards software mastery and craftsmanship whilst leveraging AI effectively. Have a look at [solve.it.com](https://solve.it.com/) if you’re interested.

I’ve spent decades teaching people to code, building tools that help developers work more effectively, and championing the idea that programming should be accessible to everyone. Through fast.ai, I’ve helped millions learn not just to use AI, but to understand it deeply enough to build things that matter.

But lately, I’ve been deeply concerned. The AI agent revolution promises to make everyone more productive, yet what I’m seeing is something different: developers abandoning the very practices that lead to understanding, mastery, and software that lasts. When CEOs brag about their teams generating 10,000 lines of AI-written code per day, when junior engineers tell me they’re “vibe-coding” their way through problems without understanding the solutions, are we racing toward a future where no one understands how anything works, and competence craters?

I needed to talk to someone who embodies the opposite approach: someone whose code continues to run the world decades after he created it. That’s why I called Chris Lattner.

Chris and I chatted on Oct 5th, 2025, and he kindly let me record the conversation. I’m glad I did, because it turned out to be thoughtful and inspiring. Check out the video for the full interview, or read on for my summary of what I learned.

## Talking with Chris Lattner[](https://www.fast.ai/posts/2025-10-30-build-to-last.html#talking-with-chris-lattner)

Chris Lattner builds infrastructure that becomes invisible through ubiquity.

Twenty-five years ago, as a PhD student, he created LLVM: the most fundamental system for translating human-written code into instructions computers can execute. In 2025, LLVM sits at the foundation of most major programming languages: the Rust that powers Firefox, the Swift running on your iPhone, and even Clang, a C++ compiler created by Chris that Google and Apple now use to create their most critical software. He describes the Swift programming language he created as “Syntax sugar for LLVM”. Today it powers the entire iPhone/iPad ecosystem.

When you need something to last not just years but decades, to be flexible enough that people you’ll never meet can build things you never imagined on top of it, you build it the way Chris built LLVM, Clang, and Swift.

I first met Chris when he arrived at Google in 2017 to help them with TensorFlow. Instead of just tweaking it, he did what he always does: he rebuilt from first principles. He created MLIR (think of it as LLVM for modern hardware an