I will add this very explicitly to head off more requests about this: we have done this before several times in several ways, and we do not at this time think it’s worth it to offer a free online Julia compute experience. I get that you think it’s crucial or whatever, and I cannot argue with an opinion, but that’s not the very well-informed opinion of Julia’s core developers. We are all very aware of what the benefits and the costs are and do not think this is worth the time and effort to make it work.
Back in the day, JuliaHub did offer a free service called JuliaBox that let people run Julia in a Jupyter notebook online that had good startup time and plotting and all that. But it was hard to develop, expensive to run, and it was before the bitcoin miners ruined everything. Since the advent of bitcoin, offering any kind of free compute is an absolute nightmare—the miners will be on anything free in no time and it takes constant vigilance to keep them away. If you don’t keep them away, the service becomes unusable for regular users. Whose job is it going to be to keep the bitcoin miners away?
Letting people run Julia in their own browser via WASM is a possibility, and a very cool one at that. But it’s just a massive amount of compiler and tooling effort to get that working. If someone wants to do it or pay for it, that would be cool, but so far no one cares about it enough to do that. I don’t think most people have any concept how expensive it would be to develop this. At least one full year’s salary of someone who is very good at compiler stuff. It’s also very unclear that it would have most of the capabilities that people expect from Julia. E.g. how would plotting work? At best I think you could get a simple text REPL working with no network.
Finally, why do you need this? This is essentially a gimmick. Yes, it’s cool that it can be done, but no one is going to actually use Julia in anger in a free online sandbox. Most people have extremely powerful multicore laptops these days. Instead we’ve focused on making the Julia installation experience as easy as possible. All you have to do is run one command and you’ll have a working Julia installed. One more pkg install command and you’ll have a working graphics stack in a few minutes. Or a fully working GPU toolchain. And it JUST WORKS. That is—frankly—fucking amazing. JuliaBox was kind of necessary back when we ran it because it was hard to get a working Julia setup with plotting and everything installed. But today? It’s so easy and reliable. Just install Julia and try it.