Simon Willison’s Weblog

Will the future of software development run on vibes? I got a few quotes in this piece by Benj Edwards about vibe coding, the term Andrej Karpathy coined for when you prompt an LLM to write code, accept all changes and keep feeding it prompts and error messages and see what you can get it to build.

Here's what I originally sent to Benj:

I really enjoy vibe coding - it's a fun way to play with the limits of these models. It's also useful for prototyping, where the aim of the exercise is to try out an idea and prove if it can work.

Where vibe coding fails is in producing maintainable code for production settings. I firmly believe that as a developer you have to take accountability for the code you produce - if you're going to put your name to it you need to be confident that you understand how and why it works - ideally to the point that you can explain it to somebody else.

Vibe coding your way to a production codebase is clearly a terrible idea. Most of the work we do as software engineers is about evolving existing systems, and for those the quality and understandability of the underlying code is crucial.

For experiments and low-stake projects where you want to explore what's possible and build fun prototypes? Go wild! But stay aware of the very real risk that a good enough prototype often faces pressure to get pushed to production.

If an LLM wrote every line of your code but you've reviewed, tested and understood it all, that's not vibe coding in my book - that's using an LLM as a typing assistant.