Introducing Render Sandboxes: a computer for every agent.

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Changelog

November 11, 2026
Improved

Reduced median first-build time for Docker-based previews by 45%

Docker-based service previews and preview environments now use the build cache from their base service’s most recent successful build. Previously, each preview’s first build started with an empty cache.

This optimization has reduced median first-build time for Docker-based previews by 45%:

Median first-build times for Docker-based previews by week.
Median first-build times for Docker-based previews by week.

Before this change (September 6 to October 28), median first-build time was 73 seconds. Since the optimization landed on October 29, the highest observed weekly median is 40 seconds.

Learn more about service previews and preview environments.