Docker Sandboxes vs Anthropic Sandbox Runtime
Choose Docker Sandboxes for running coding agents unsupervised on a laptop with microVM isolation; choose Anthropic Sandbox Runtime for lightweight local sandboxing of coding agents and CLI tools. Docker Sandboxes uses MicroVM isolation; Anthropic Sandbox Runtime uses OS-level (Seatbelt / bubblewrap) isolation and is open source.
Docker Sandboxes vs Anthropic Sandbox Runtime at a glance
| Attribute | Docker Sandboxes | Anthropic Sandbox Runtime |
|---|---|---|
| What it is | Docker’s sbx CLI for running AI coding agents in microVM sandboxes on your machine, with an experimental Docker-hosted cloud. | Open-source CLI and library (srt) that restricts filesystem and network access for any local process at the OS level, without a container or VM. |
| Isolation | MicroVM with a separate kernel per sandbox, each running its own private Docker Engine | OS-level: macOS Seatbelt profiles; Linux bubblewrap with network namespace removed and traffic forced through host proxies; Windows support in alpha |
| Open source | No | Yes (Apache-2.0) |
| Self-host / BYOC | Yes / No | Yes / Not documented |
| SDKs | sbx CLI, TypeScript (cloud), REST API (cloud) | CLI (srt), TypeScript (npm) |
| Cold start (vendor claim) | Not documented | Not documented |
| Max session | Local: persist until removed. Cloud: governed by configured time-to-live | Not documented |
| Persistence | Local sandboxes keep packages and agent state until removed; cloud supports snapshots and volumes; sbx move copies a sandbox between local and cloud | Operates on the host filesystem; writes only to explicitly allowed paths |
| GPU | Local only, GPU passthrough on supported hosts; not in cloud sandboxes | Not documented |
| Networking | Deny-by-default network policy; outbound TCP proxied through the host; credentials injected by a host-side proxy so raw keys never enter the VM | Deny-all by default; domain allowlists and denylists enforced by host HTTP and SOCKS5 proxies |
| Pricing | CLI and local sandboxes free, including commercial use. Cloud sandboxes metered per second; per-unit rates not published | Free and open source |
| Compliance | Not documented | Not documented |
| Best for | Running coding agents unsupervised on a laptop with microVM isolation | Lightweight local sandboxing of coding agents and CLI tools |
Verified November 8, 2026 from each provider’s documentation. Cold-start figures are vendor claims, not our measurements.
Which should you choose?
Choose Docker Sandboxes if…
- You want to let a coding agent run unattended on your laptop safely
- Your agent needs to build and run Docker containers
- You want local sandboxes for free
Choose Anthropic Sandbox Runtime if…
- You want near-zero-overhead sandboxing for a local agent or CLI
- You need strict network allowlisting on a developer machine
- You want to wrap existing tools without containers
Both are worth piloting with your own image and region. See the full Docker Sandboxes profile and Anthropic Sandbox Runtime profile, or the complete comparison.
Frequently asked questions
Is Docker Sandboxes or Anthropic Sandbox Runtime better for AI agents?
Which is open source, Docker Sandboxes or Anthropic Sandbox Runtime?
How do Docker Sandboxes and Anthropic Sandbox Runtime isolate code?
Sources
Cite this page
Agent Sandboxes. (2026). Docker Sandboxes vs Anthropic Sandbox Runtime. agentsandboxes.org. Last reviewed November 8, 2026. https://agentsandboxes.org/compare/docker-sandboxes-vs-anthropic-srt/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.