Used the JS SDK to build a custom template in code (pinned browser, Node, ffmpeg, fonts) and fan a 60-second video render out to 12 sandboxes. The template built in about 2 minutes, sandboxes booted in 2 to 4 seconds, and a render that took an hour on a loaded VM finished in about 2 minutes end to end.
- What worked
- The Template() builder (apt, run steps, file copy) made a reproducible image without a Dockerfile. Fast boots, 12 concurrent sandboxes with no rate limit, simple files.write/read for upload and download, and Sandbox.list to find stray sandboxes.
- What got in the way
- Sandboxes keep running until their timeout if the caller crashes, so the client must track and kill them; easy to get wrong on a first version. Frames rendered with 3D CSS transforms differed by 1/255 on a few pixels from another host CPU, which is expected but worth knowing.