Cloudflare has redesigned Cloudflare Containers to meet the needs of AI agents that create isolated Linux environments for each task, rather than relying on fixed settings defined at deployment. The update allows code to select the container image and resource type at runtime, with a new scheduling path linked to Durable Objects, startup times more than six times faster, and filesystem snapshots currently available in public beta.
In the Burst TTI Benchmark independently conducted by ComputeSDK, the median fell from 4.049 seconds to 648 milliseconds, while the 95th-percentile time dropped from 5.839 to 910 milliseconds, and the 99th percentile from 6.717 to 1.129 seconds. Cloudflare says an initial stress test successfully launched 100,000 containers in 5.387 seconds across six locations, though these are preliminary figures that do not necessarily represent all usage patterns.
What changes in practice?
Choosing the container image and resource size previously required creating separate applications and namespaces for each combination, then routing tasks among them. With the new durable_object policy, code can choose a Node.js or Python environment, as well as an instance type such as standard-1 or standard-2, after determining the task’s requirements. Adding a new environment therefore becomes a code change rather than the deployment of a new application.
The design also moves update logic to the Durable Object associated with each container. A developer can pin a specific image for an active project, apply a gradual rollout to a percentage of new environments, or defer migration to a later session or natural save point, then roll back by changing the image used at the next startup.
Ready-made environments and restorable snapshots
To reduce system setup time, Cloudflare introduced the cloudflare/debian-trixie image, which includes Debian Trixie Slim and Node.js 24.20.0 LTS. It can be run without creating a Dockerfile or building and pushing an image to Cloudflare, after which the repository, packages, and tools can be configured from inside the container using exec().
Filesystem snapshots make it possible to save a workspace after installing dependencies and making changes, then restore it in a later session. The same snapshot can also be used as an immutable starting point for multiple environments, which suits agent tests that require the repository, tools, and input files to remain identical across attempts.
Why does this news matter?
The update makes the container a computational extension of the Durable Object: the latter retains identity, state, policies, and lifecycle, while the container provides a Linux workspace that can be stopped when work pauses and resumed when needed. This matters to developers of coding agents, evaluation sessions, reinforcement-learning systems, and tasks that span days and need to retain files.
The uses mentioned by Cloudflare include integrations with Cursor Cloud Agents, Devin Outposts, OpenAI Agents API, and Claude Managed Agents, in addition to examples from Base44 and Kilo Code. The core value here is not merely faster startup, but moving environment decisions, migration policy, and state preservation into the application’s own logic.
Compatibility and migration path
The new durable_object policy and filesystem snapshots are available in public beta, while some of the new capabilities remain available only through ctx.container. Cloudflare will maintain Container class and Legacy Sandbox class until December 31, 2026; current deployments will continue after that date, but these classes will not receive updates. The company recommends migrating to Durable Object and using this.ctx.container directly, while Sandbox SDK 1.0 has become a toolkit that operates inside the developer’s Durable Object class rather than an independent base class.