Code and Let Live
1–10 of 195 posts
Re: Code and Let Live
#2Like it, a lot. I think the future of software is going to be unimaginably dynamic. Maybe apps will not have statically defined feature sets, they will adjust themselves around what the user wants and the data it has access to. I’m not entirely sure what that looks like yet, but things like this are a step in that direction.
Re: Code and Let Live
#3This sounds great and it's roughly what exe.dev is doing too. Coincidence?
Re: Code and Let Live
#4This sounds great and it's roughly what exe.dev is doing too. Coincidence?
This has been in the works for quite awhile here. We put a long bet on "slow create fast start/stop" --- which is a really interesting and useful shape for execution environments --- but it didn't make sense to sandboxers, so "fast create" has been the White Whale at Fly.io for over a year.
Re: Code and Let Live
#5Like it, a lot. I think the future of software is going to be unimaginably dynamic. Maybe apps will not have statically defined feature sets, they will adjust themselves around what the user wants and the data it has access to. I’m not entirely sure what that looks like yet, but things like this are a step in that direction.
> I think the future of software is going to be unimaginably dynamic.
>...I’m not entirely sure what that looks like yet, but things like this are a step in that direction.
This made me stop and think for a moment as to what this would look like as well. I'm having trouble finding it, but I think there was a post by Joe Armstrong (of Erlang) that talked about globally (as in across system boundaries, not global as in global variable) addressable functions?
Re: Code and Let Live
#6I'm really excited about https://sprites.dev/ - it hits two of my favourite problems at once:
1. Developer environment sandboxes. This is a cheap and convenient way to run Claude Code / Codex CLI / etc in YOLO mode in a persistent sandboxed VM with a restricted blast radius if something goes wrong.
2. Sandbox API. Fly now have a product that lets me make a simple JSON API call to run untrusted code in a new sandbox. There's even snapshotting support so I can roll back to a known state after running that code.
I wrote more a bunch more about this here: https://simonwillison.net/2026/Jan/9/sprites-dev/
Re: Code and Let Live
#7So this is neat and useful and I think will/should get traction.
So let's say sprite is my building/dev ground floor. I get my thing/app to where I want it, but at the end of the day I think my thing/app is so awesome that it should be a production app for the whole world, and, I want to actually deploy it on fly, say.
Have you guys thought about that workflow, and what it might take to push button/migrate a sprite app over to fly?
Also, any plans for GPU sprites?
Re: Code and Let Live
#8Could you clarify what this actually is?
Would I think of this as an EC2 instance which automatically and quickly scales to zero, with pricing only for resources consumed? (CPU and RAM when up, and disk all the time?)
Re: Code and Let Live
#9Could you clarify what this actually is? Would I think of this as an EC2 instance which automatically and quickly scales to zero, with pricing only for resources consumed? (CPU and RAM when up, and disk all the time?)
Yeah that's about right.
It's a fast starting and fast pausing persistent VM, with a ton of built in developer tools (including a preconfigured Claude Code) and an extra JSON API for executing commands within it so you can treat it as a sandbox.
You may find my writeup here useful: https://simonwillison.net/2026/Jan/9/sprites-dev/
Re: Code and Let Live
#10This sounds great and it's roughly what exe.dev is doing too. Coincidence?
I have just now learned about exe.dev and it looks awesome.
I really hate that modern development means not having persistent disk. I’m glad there are new options coming out which let you do this in and easier way than managing my own EC2 instances!