CapabilitiesIsolation
Your own image
Start machines from your own Dockerfile or image instead of the provider's default.
Short answer: 9 of 16 providers offer it fully: Agent 37, Blaxel, Cloudflare Sandbox, Daytona, E2B, Modal, Runtime, Tensorlake and Vercel Sandbox. With a catch: InstaBox, Morph, Sandboxer and boxd. Checked 29 October 2026.
Who offers it
Part of Isolation: what kind of computer you get, which explains why it matters.
Fully: Agent 37, Blaxel, Cloudflare Sandbox, Daytona, E2B, Modal, Runtime, Tensorlake and Vercel Sandbox. With a catch: boxd, InstaBox, Morph and Sandboxer. Not at all: Boat, Lizard and Sprites.
docs-confirmed “You can run an Agent37 instance from any Docker image.” Source
docs-confirmed “Create reusable sandbox images with pre-configured tools, languages, and frameworks using Dockerfiles.” Source
docs-confirmed “image = "./Dockerfile"” Source
Virtual-machine sandboxes cannot be built from a Dockerfile; containers and GPU sandboxes can.
docs-confirmed “VM snapshots (Linux VM and Windows) cannot be built from a Dockerfile.” Source
Multi-stage Dockerfiles are not supported.
docs-confirmed “Use any Docker image from Docker Hub or other registries” Source
docs-confirmed “To load an image from a public registry, just pass the image name, including any tags, to Image.from_registry” Source
docs-confirmed “You can build an image from any Dockerfile.” Source
docs-confirmed “Tensorlake supports defining sandbox images in Python, TypeScript, or a raw Dockerfile.” Source
A custom image does not run its Docker start command; Vercel starts the sandbox itself.
docs-confirmed “store the image in Vercel Container Registry (VCR) and create the sandbox with a custom image” Source
The catch: You cannot bring a Docker image; the way to get your own setup is to customise a machine and start new ones from a snapshot of it.
docs-confirmed “To start every sandbox with your own toolchain, dependencies, and services already in place, create them from a snapshot instead” Source
The catch: You pick from fixed images or a saved copy; a different starting image needs an operator to build one for you.
docs-confirmed “An operator can also build a template from a public Debian- or Ubuntu-based image” Source
The catch: There is no documented way to import your own image; you start from a template or from a snapshot you saved.
docs-confirmed “Every devbox is created from a template that integrates with our secrets manager” Source
The catch: You cannot start from your own image; you set a machine up and save its disk as a template.
docs-confirmed “Set up one sandbox the way you want it, then save its disk under a name with sbx snapshot” Source
Note: There is no way to bring your own image or build recipe; you install what you need and save a copy of the machine instead.
docs-confirmed “No. boat has no custom image and no Dockerfile build.” Source
Note: You choose from a fixed list of templates and cannot upload your own image.
docs-confirmed “The public CLI does not provide a custom-template upload flow.” Source
Note: There is no documented way to start a Sprite from your own image.
docs-confirmed “It does not touch the base image itself” Source
Related
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