AI will never be able to create a browser, just as AI was never able to defeat a chess grandmaster.
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When AI 'builds a browser,' check the repo before believing the hype
21–30 of 145 posts
Re: When AI 'builds a browser,' check the repo before believing the hype
#22If you want to learn more about the Cursor project directly from the source I conducted a 47 minute interview with Wilson Lin, the developer behind FastRender, last week.
We talked about dependencies, among a whole bunch of other things.
You can watch the full video on YouTube or read my extracted highlights here: https://simonwillison.net/2026/Jan/23/fastrender/
Re: When AI 'builds a browser,' check the repo before believing the hype
#23I love the quote from Gregory Terzian, one of the servo maintainers: > "So I agree this isn't just wiring up of dependencies, and neither is it copied from existing implementations: it's a uniquely bad design that could never support anything resembling a real-world web engine." It hurts, that it wasn't framed as an "Experiment" or "Look, we wanted to see how far AI can go - kinda failed the bar." Like it is, it pour…
That was from a conversation here on Hacker News the other day: https://news.ycombinator.com/item?id=46624541#46709191
Re: When AI 'builds a browser,' check the repo before believing the hype
#24> According to Perplexity, my AI chatbot of choice, this week‑long autonomous browser experiment consumed in the order of 10-20 trillion tokens and would have cost several million dollars at then‑current list prices for frontier models. Don't publish things like that. At the very least link to a transcript, but this is a very non-credible way of reporting those numbers.
That implies a throughput of around 16 million tokens per second. Since coding agent loops are inherently sequential—you have to wait for the inference to finish before the next step—that volume seems architecturally impossible. You're bound by latency, not just cost.
Re: When AI 'builds a browser,' check the repo before believing the hype
#25Earlier quoted context omitted.
That's what got me. I've never written a browser from scratch but just telling me that it took millions of lines of code made me feel like something was wrong. Maybe somehow that's what it takes? But I've worked in massive monorepos that didn't have 3million lines of code and were able to facilitate an entire business's function.
To be fair, it easily takes 3 million lines of code to make a browser from scratch. Firefox and Chrome both have around ten times that(!) – presumably including tests etc. But if the browser is in large part third-party libraries glued together, that definitely shouldn't take 3 million lines.
FastRender isn't "in large part third-party libraries glued together". The only dependency that fits that bill in my opinion is Taffy for CSS grid and flexbox layout.
The rest is stuff like HarfBuzz for font rendering which is an entirely cromulent dependency for a project like this.
Re: When AI 'builds a browser,' check the repo before believing the hype
#26I’m super impressed by how "zillions of lines of code" got re-branded as a reasonable metric by which to measure code, just because it sounds impressive to laypeople and incidentally happens to be the only thing LLMs are good at optimizing.
Citing the ability to turn on an endless faucet of code as a benefit and not a liability should be disqualifying.
Re: When AI 'builds a browser,' check the repo before believing the hype
#27I don't think the point was to say "look, AI can just take care of writing a browser now". I think it was to show just how far the tools have come. It's not meant to be production quality, it's meant to be an impressive demo of the state of AI coding. Showing how far it can be taken without completely falling over. EDIT: I retract my claim. I didn't realize this had servo as a dependency.
It didn't have Servo as a dependency.
Take a look in the Cargo.toml: https://github.com/wilsonzlin/fastrender/blob/19bf1036105d4e...
Re: When AI 'builds a browser,' check the repo before believing the hype
#28I love the quote from Gregory Terzian, one of the servo maintainers: > "So I agree this isn't just wiring up of dependencies, and neither is it copied from existing implementations: it's a uniquely bad design that could never support anything resembling a real-world web engine." It hurts, that it wasn't framed as an "Experiment" or "Look, we wanted to see how far AI can go - kinda failed the bar." Like it is, it pour…
That was from a conversation here on Hacker News the other day: https://news.ycombinator.com/item?id=46624541#46709191
I wish your recent interview had pushed much harder on this. It came across as politely not wanting to bring up how poorly this really went, even for what the engineer intended.
They were making claims without the level of rigor to back them up. There was an opportunity to learn some difficult lessons, but—and I don’t think this was your intention—it came across to me as kind of access journalism; not wanting to step on toes while they get their marketing in.
Re: When AI 'builds a browser,' check the repo before believing the hype
#29Earlier quoted context omitted.
That's what got me. I've never written a browser from scratch but just telling me that it took millions of lines of code made me feel like something was wrong. Maybe somehow that's what it takes? But I've worked in massive monorepos that didn't have 3million lines of code and were able to facilitate an entire business's function.
To be fair, it easily takes 3 million lines of code to make a browser from scratch. Firefox and Chrome both have around ten times that(!) – presumably including tests etc. But if the browser is in large part third-party libraries glued together, that definitely shouldn't take 3 million lines.
Depending on how functional you want the browser to be. I can technically write a web browser in a few lines of perl but you wouldn't get any styling, let alone javascript. Plus 90% of the code is likely going to fixing compatibility issues with poorly designed sites.
Re: When AI 'builds a browser,' check the repo before believing the hype
#30Just had my manager submit 3 PRs in a language he doesn’t understand (rust) and hasn’t ran or tested and is demanding quick reviews for hundreds of LoCs. These are tools but some people are clueless..