Cloudflare updated Containers on September 30 so an application can choose a sandbox’s image and compute size when an agent starts a task. Previously, those combinations were configured as separate applications ahead of time.
The new scheduling path also reduces startup delay. In the ComputeSDK benchmark reproduced in Cloudflare’s report, launching 100 sandboxes concurrently produced a median time to first interaction of 648 milliseconds, down from 4.049 seconds on the previous path. That measures startup, not the time an agent needs to finish its assignment.
Filesystem snapshots, released in public beta, let an application save repositories, installed dependencies and edits, then restore those files in a new container. Multiple sandboxes can start from the same immutable snapshot when an evaluation needs a consistent starting point.
The container’s Durable Object remains its controller. Application code decides which image to start and when to stop or replace it, allowing active projects to keep their current environment while new sessions try an updated one.
These features require the native Containers API. They are not available through the older Container or Sandbox classes, which Cloudflare said it would maintain through December 31, 2026.