Cloudflare starts 100 concurrent sandboxes 6.2x faster at the median

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Cloudflare Containers are Linux workspaces for agents, and the latest changes make them quicker to start and easier to configure. In ComputeSDK’s Burst TTI Benchmark, which launched 100 sandboxes concurrently, median startup fell from 4.049 seconds to 648 milliseconds, a 6.2x improvement.

Here’s what changed:

• The same test measured 910 milliseconds at p95 and 1,129 milliseconds at p99.
• The durable_object scheduling policy is in public beta for all and lets a Durable Object select an image and instance type at runtime, rather than requiring a separate deployed application for every pairing.
• Filesystem snapshots can save and restore a workspace, including files and setup, or provide a shared starting point for isolated sandboxes.
• The prebuilt cloudflare/debian-trixie image includes Debian Trixie Slim and Node.js 24.20.0 LTS, and can start without first building and pushing a Docker image.

One catch: The new capabilities are available only through the native ctx.container API. Legacy Container and Sandbox classes will be maintained through December 31, 2026, but will not receive updates after that date.

Try it: In your Durable Object, declare the images it can use, then call this.ctx.container.start({ image, instance, ... }). For a ready-made base, use cloudflare/debian-trixie.

Sources: blog.cloudflare.com