AI agents write code now, and that code has to run somewhere. When an agent analyzes a spreadsheet or tests a fix, it executes code it wrote a moment ago, code no person has reviewed. Running that on a real server is asking for trouble. So the agent gets a sandbox: a fresh, isolated machine that starts in under a second and gets thrown away when the job is done.
CodeInstances.com is the name for that layer. “Instance” is the cloud’s own word for a running machine, and a code instance is one that exists only to run code. The plural suits a service that starts thousands of them an hour, each created and destroyed through a small API.
The big platforms are already in
Every serious agent product needs this, and the money has followed. Startups built around agent sandboxes have raised venture rounds. Cloudflare, Google, Railway and Deno have each shipped sandboxes of their own. When companies that size build a product line around a need, the need is real and the spending has only started.
Demand comes from everywhere at once: coding assistants, data-analysis tools, browser agents, AI tutors that run students’ code, evaluation harnesses testing models by the thousand. Each needs short-lived, locked-down machines on demand, and pays for them by the second.
The hard part is doing two things at once. A sandbox has to start fast enough that the agent never stalls, and stay sealed tight enough that hostile code can’t touch the host or wander onto the network. Providers that get both right can charge for it.
Who it’s for
A sandbox startup that wants a name saying exactly what it sells. An agent platform adding hosted execution. A cloud or hosting company launching a developer brand for its isolation tech. An AI company building its own runtime. The domain reads in one pass and sits as naturally on a pricing page as on a homepage.
Agents write more code every month. Every line needs somewhere safe to run.