Comparison

Containarium vs Docker Sandboxes

Docker Sandboxes run a coding agent in a microVM on your laptop — and, since September 2026, in Docker's cloud — so it can't touch your host. Containarium gives an agent a persistent box on a server you host, with a public hostname and an MCP server. One protects your laptop; the other gives the agent somewhere else to live.

Choose Containarium when…

The agent's box should outlive a session and keep running services.
You want the environment on your own server, not a laptop or Docker's cloud.
The agent should host what it builds on a public HTTPS hostname.
You want the platform under Apache 2.0, with no subscription for team features.

Choose Docker Sandboxes when…

You want to run Claude Code, Codex, Gemini CLI or Copilot CLI unsupervised on your laptop.
You want microVM isolation with the agent's own Docker daemon inside.
You already live in Docker Desktop.
Sessions are disposable: delete and start fresh in seconds.

Guard the laptop vs move the agent off it.

Side-by-side

Dimension	Containarium	Docker Sandboxes
Where it runs	A VM or cluster you host (or Containarium Cloud)	Your own machine; Docker-managed cloud since Sept 2026
Isolation	LXC system container or Kubernetes pod (optional gVisor)	MicroVM with its own Docker daemon, filesystem and network
Lifecycle	Persistent until you delete it	Disposable sessions; cloud sessions up to 24 hours
Public reach	Routable hostname with TLS; custom domains	Local to the machine the sandbox runs on
Agent interface	MCP server in every box + CLI + SSH	`sbx` CLI that launches a supported agent (Claude Code, Codex, Gemini CLI, Copilot CLI, Kiro)
Network control	Per-tenant eBPF egress allowlists	Allow and deny lists
Pricing	OSS: your VM's cost. Cloud: free tier, then usage	Cloud from $0.07/hr (1 vCPU / 2 GiB) to $1.12/hr (16 vCPU / 32 GiB), per second

Docker Sandboxes details checked against its public docs and pricing pages in September 2026. Check Docker Sandboxes's own docs for current specifics.

Different problems

Docker Sandboxes answer "how do I let an agent run with approvals off without risking my machine?" — a microVM around the agent, with its own Docker daemon so it can still build containers. That is the lighter tool for a solo developer, and a good one.

Containarium answers "where should the agent live?" A box is a long-lived server-side machine: it keeps its toolchain, runs services, and publishes them on a hostname with containarium expose-port. The agent can be driven from any laptop — or none.

Isolation, honestly

A microVM is a stronger boundary than a shared-kernel container. Containarium's boundary is the box plus SSH-only access and eBPF egress policy; for truly hostile code, read how to run untrusted agent code before you choose.

FAQ

What is the difference between Containarium and Docker Sandboxes?

Docker Sandboxes run a coding agent inside a microVM, on your laptop or in Docker's cloud, to protect the host. Containarium gives an agent a persistent Linux box on a server you host, with a public hostname and an MCP server built in.

Can Docker Sandboxes host a service on a public URL?

Docker Sandboxes are designed around protecting the machine they run on, not publishing services. Containarium publishes a box's port on a TLS hostname with one CLI command.

Which has stronger isolation?

Docker Sandboxes use microVMs, a stronger boundary than Containarium's shared-kernel LXC containers. Containarium adds SSH-only access with no cluster credentials in the box, and eBPF egress allowlists.