CubeSandbox is Tencent Cloud's open-source, self-hosted sandbox service for AI agents, built on RustVMM and KVM.
Each sandbox is a hardware-isolated microVM with its own kernel that starts in tens of milliseconds, and the service is compatible with the E2B SDK so agent code can switch from E2B Cloud by changing one environment variable.
- 01
~60 ms average cold start and under 5 MB memory overhead per sandbox
- 02
Dedicated kernel per sandbox in its own microVM for hardware-level isolation
- 03
Drop-in E2B SDK compatibility, including an E2B-compatible volume framework
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Copy-on-write snapshots, instant clone, rollback and cross-node pause/resume
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eBPF egress filtering and an L7 security proxy that injects credentials so keys never enter the sandbox
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Single-node, multi-node, Terraform, Kubernetes and native ARM64 deployments
Open Source
Free and open source under Apache-2.0 (with third-party components under their own licenses). You self-host it on your own x86_64 Linux servers with KVM, so costs are your infrastructure; no paid tier is listed in the repository.
Best for
Platform and agent-infrastructure teams who want to self-host high-density, secure code-execution sandboxes for coding agents or RL workloads instead of relying on a hosted sandbox API.
Not ideal for
Individual developers without access to KVM-capable Linux servers, or teams that prefer a fully managed sandbox service over operating their own cluster.
A serious, fast-moving open-source alternative to hosted agent sandboxes, notable for E2B compatibility and microVM isolation at container-like density; best for teams ready to run their own infrastructure.
v0.7.2 (2026-09-24) sped up cross-node restore from S3 with a local whole-object cache and coalesced reads, and added a JuiceFS volume plugin; v0.7 introduced cross-node pause/resume and moved node management into CubeOps.
As of
Is CubeSandbox free?+
Yes - CubeSandbox is Open Source. Free and open source under Apache-2.0 (with third-party components under their own licenses). You self-host it on your own x86_64 Linux servers with KVM, so costs are your infrastructure; no paid tier is listed in the repository.
Is CubeSandbox open source?+
Yes - CubeSandbox is open source. Free and open source under Apache-2.0 (with third-party components under their own licenses). You self-host it on your own x86_64 Linux servers with KVM, so costs are your infrastructure; no paid tier is listed in the repository.
Who is CubeSandbox best for?+
Platform and agent-infrastructure teams who want to self-host high-density, secure code-execution sandboxes for coding agents or RL workloads instead of relying on a hosted sandbox API.
Who is CubeSandbox not ideal for?+
Individual developers without access to KVM-capable Linux servers, or teams that prefer a fully managed sandbox service over operating their own cluster.
What are the best CubeSandbox alternatives?+
The closest CubeSandbox alternatives on ai.dosa.dev are Pieces for Developers, agenttrace, Vibe Kanban - all listed under Developer Productivity & Workflow.
Who makes CubeSandbox?+
CubeSandbox is developed by Tencent Cloud. It is listed in the Developer Productivity & Workflow category on ai.dosa.dev.
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