- https://github.com/simonw/denobox is a new Python library that gives you the ability to run arbitrary JavaScript and WASM in a sandbox provided by Deno, because it turns out a Python library can depend on deno these days. I built that on my phone in bed yesterday morning.
- https://github.com/simonw/pwasm is a WebAssembly runtime written in pure Python with no dependencies, built by feeding Claude Code the official WASM specification along with its conformance test suite and having it hack away at that (again via my phone) to get as many of the tests to pass as possible. It's pretty slow and not really useful yet but it's certainly interesting.
- https://github.com/datasette/datasette-transactions is a Datasette plugin which provides a JSON API for starting a SQLite transaction, running multiple queries within it and then executing or rolling back that transaction. I built that one on my phone on a BART (SF Bay Area metro) trip.
- https://github.com/simonw/micro-javascript is a pure Python, no dependency JavaScript interpreter which started as a port of MicroQuickJS. Here's a demo of that one running in a browser https://simonw.github.io/micro-javascript/playground.html - that's my JavaScript interpreter running inside Python running in Pyodide in WebAssembly in your browser of choice, which I find inherently amusing.
All of those are from the past three weeks. Most of them were built on my phone while I was doing other things.
I am not at all an AI sceptic, but probably less impressed by what LLMs are capable of.
Looking at these projects, I have a few questions:
1. These seem to be fairly self-contained and well specified problems, which is the best case scenario for “vibe coding”. Do you have any examples of projects where the solution was somewhat vague and open-ended? If not, how do you think Claude Code or similar would perform?
2. Did you feel excited or energized by having an LLM implement these projects end-to-end? Personally, I find LLMs useful as a closely guided assistant, particularly to interactively explore the space of solutions. I also don’t feel energized at all by having it implement anything non-trivial end to end, outside of writing tests (and even then, not all types of tests!).
3. Do you think others would find these projects useful? In particular, if you vibe coded them, why couldn’t someone else do the same thing? And once these projects are picked up by future model training runs, they’ll probably be even easier to one shot, reducing the value even further.
Let me provide an example of what I mean by (2), at least in the context of hobbyist dev. I could have Claude Code vibe code a Gameboy emulator and it would probably do a fine job given that it’s a well specified problem that is likely well represented in its training data. But the process would neither be exciting nor energizing. I would rather spend hours gradually getting more and more working and experience the fruits of my labor (I did this already btw).
At $DAYJOB, I simply do not have confidence in an LLM doing anything non-trivial end to end. Besides, the complexity remains in defining the requirements and constraints, designing the solution, gaining consensus, and devising a plan for implementation. The goal would be for the LLM to pick up discrete, well defined chunks of work.
I have another project in the works in Go which is proving to be a ton of fun from a software design perspective, but it's not ready for outside eyes just yet.
"Did you feel excited or energized by having an LLM implement these projects end-to-end"
I'm enjoying myself so much right now. My BART rides have never been this entertaining before!
"Do you think others would find these projects useful? In particular, if you vibe coded them, why couldn’t someone else do the same thing?"
I don't think many developers have the combined taste and knowledge necessary to spin up Denobox or django-transactions. They both solve problems that I'm very confident need solving, but I expect to have to explain why those matter in some detail to all but a very small group of people who share my particular interests.
The other two are pretty standard - I suggest anyone who wants to learn more about JavaScript interpreters or WASM runtimes try something similar in the language of choice as a learning exercise.
Thanks for sharing, that project indeed looks useful.
> My BART rides have never been this entertaining before!
Not clear if this is snark, but if vibe coding on a train ride is actually energizing, then good for you haha.
> I don't think many developers have the combined taste and knowledge necessary to spin up Denobox or django-transactions.
Perhaps, but that’s just for now. What do you do when your “taste” no longer makes a difference? In other words, looking at the bigger picture, do you like where the field is going?
> I suggest anyone who wants to learn more about JavaScript interpreters or WASM runtimes try something similar in the language of choice as a learning exercise.
Agreed, but depending on learning style, vibe coding such a project might not teach you anything new at all :)
> I have another project in the works in Go which is proving to be a ton of fun from a software design perspective, but it's not ready for outside eyes just yet.
As a long-time user of the language I'm happy see that Go seems to be excellent for LLM agent development. The language is simple, there's only one way to do loops etc. It hasn't changed that much syntax wise (I think `any` is the only thing that LLMs miss).
Gofmt (or goimports) makes sure all code looks the same, there are VERY robust linters and a built-in testing framework so the LLM only needs to know one. And the code won't even compile if there are unused variables or other cruft.
It might be boring or verbose, but it's also very predictable and simple. All things LLMs like :D
Based on those, it seems you are not actually using them to create big codebases from scratch, but rather for problems that would normally take quite a while, not because they are inherently difficult to implement, but because you would normally have to spend considerable time on the finicky implementation details.
I think that's the reason why LLMs work so well for some like you, and generate slop for others, because if you let them alone with projects that require opinionated code and actual decision making they most often don't grasp the users intention well or worse misinterpret it so confidently that you end up with something with all the wrong opinions and decisions compounding path-dependently into the strangest and most useless slop.
"for problems that would normally take quite a while, not because they are inherently difficult to implement, but because you would normally have to spend considerable time on the finicky implementation details"
Yes, exactly! How amazing is it that we have technology now that lets us quickly build projects where we would normally have to spend considerable time on the finicky implementation details?
Pretty nice I guess. Cool even. Impressive! And I only say this , just in case, for someone else maybe, ehh—is that it? Because that’s totally fine with me, same experience actually funny that, really impressive tech btw! Very nice. Just, maybe, do the CEOs know that? When people talk of “not having to code anymore”—do they know that this is how it’s described by one of its most prominent champions today?
Not that I mind, of course. As you said: amazing!
Maybe someone just check in with the CEOs who were in the news recently talking about their work force…
> When people talk of “not having to code anymore”
You should reinterpret that as "not having to type the code out be hand any more". You still need a significant depth of coding knowledge and experience to get good results out of these things. You just don't need to type out every variable declaration and for loop yourself any more.
Every single tool or utility you have in the back of your head, you can just make it in a few hours of wall-clock time, minutes of your personal active time.
Like I wanted a tool that can summarise different sources quickly, took me ~3 hours to build it using llm + fragments + OpenAI API.
Now I can just go `q <url>` in my terminal and it'll summarise just about anything.
Then I built a similar tool that can download almost anything `dl <url>` will use yt-dlp, curl and various other tools depending on the domain to download the content.
Another lens is that many people either have terrible written communication skills, do not intuitively grasp how to describe a complex system design, or both. And yet, since everyone is a genius with 100% comprehensibility in their own mind, they simply aren't aware that the problem starts with them.
Well I think it also has to do with communication with LLMs being different to communication with humans. If you tell a developer "don't do busywork" they surely wouldn't say "Oh the repo looks like a trash dump, but no busywork so I'm not going to clean it up, quickly document that as canonical structure, then continue"
$200 to Anthropic, $20 to OpenAI, ~$10 in API fees for various other services, and I get GitHub Copilot in VS Code for free as an open source developer.
Mid-Senior in MENA. My monthly Salary is around 740 USD (Converted), and while I exaggerated that more than 50% figure, 200 USD/m is still a gigantic chunk of money to spend on something with dubious return on investment.
> gigantic chunk of money to spend on something with dubious return on investment.
There is nothing dubious about it. It’s providing verifiable value. Tasks that we would have set for developers or UX’ers last year are solved by it. At 1/50 of the cost, and with great scaling because the tasks are solved faster than you would even be able to explain them to a human and we can initiate 5-10 parallel tracks without having to onboard new people.
And sure it might not make sense to give a 200$/m AI tool to a worker you are paying 800$ but when we have devs that are paid 8000$/m then it’s great return on value to have one person being 10 times as productive at 8200$ instead of spending 80000$/m on ten developers just to be able to say we are doing authentic AI free artisanal software development.
You keep saying you "built" this or that, but did you really?
Of course I don't know for sure if you had any substantial input other than writing a few paragraphs of prompt text and sending Claude some links, because I didn't witness your workflow there. But I think this is kind of what irks some people including myself.
What's stopping me from "building" something similar also? Maybe I won't be as fast as you since you seem to be more experienced with these tools, but at the end of the day, would you be able to describe in detail what got built without you asking Claude about it? If you don't know anything about what you built other than just prompting an AI, in my opinion you didn't actually "build" anything -- Claude did.
Based on your comment history it seems like you're making an assumption about my intentions here, but I'll bite anyway.
When you build a table, you use a tool as a means to an end, i.e. you use the tool to cut and shape, but you are fully in control and engaged in the process. When you prompt an LLM, you tell it what to do and it does something for you. How is that not the same as telling someone else to build the table for you? You don't say "I built the table", you say "I got someone else to build the table for me."
I think it's great that simonw responded with some information on his process, that definitely helps provide perspective on how he engaged with Claude to make these projects.
- https://github.com/simonw/denobox is a new Python library that gives you the ability to run arbitrary JavaScript and WASM in a sandbox provided by Deno, because it turns out a Python library can depend on deno these days. I built that on my phone in bed yesterday morning.
- https://github.com/simonw/pwasm is a WebAssembly runtime written in pure Python with no dependencies, built by feeding Claude Code the official WASM specification along with its conformance test suite and having it hack away at that (again via my phone) to get as many of the tests to pass as possible. It's pretty slow and not really useful yet but it's certainly interesting.
- https://github.com/datasette/datasette-transactions is a Datasette plugin which provides a JSON API for starting a SQLite transaction, running multiple queries within it and then executing or rolling back that transaction. I built that one on my phone on a BART (SF Bay Area metro) trip.
- https://github.com/simonw/micro-javascript is a pure Python, no dependency JavaScript interpreter which started as a port of MicroQuickJS. Here's a demo of that one running in a browser https://simonw.github.io/micro-javascript/playground.html - that's my JavaScript interpreter running inside Python running in Pyodide in WebAssembly in your browser of choice, which I find inherently amusing.
All of those are from the past three weeks. Most of them were built on my phone while I was doing other things.