A code sandbox is isolated infrastructure, created on demand and thrown away afterward. Code runs inside it and can't reach your files, your network, or anyone else's sandbox. The name is literal: it's a place built for making a mess.
Sandboxes went from niche to obsession because of AI. An agent that writes code has to run that code to find out whether it worked, and the whole value of the loop is that it tries things that might be wrong. Modal, E2B, and OpenAI's Codex Cloud all sell a version of this.
