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Best open-source and self-hosted agent sandboxes

Answer in brief

For self-hosting, our top picks are E2B, Kubernetes Agent Sandbox and Microsandbox. We weight licence openness, isolation strength, maturity and operational effort.

By the Agent Sandboxes editors · Updated

What self-hosting need from a sandbox

Self-hosting gives control over data, network and cost. When comparing open-source options, look at:

  • Licence (Apache-2.0 vs copyleft) and whether the full backend — not just the SDK — is open.
  • Isolation you get out of the box, and whether it needs bare metal or nested virtualization.
  • Operational effort: Kubernetes-native or single-node, warm pools, snapshots.

See also the self-hosting guide.

Best open-source and self-hosted agent sandboxes, ranked

  1. E2B

    Open-source cloud sandboxes for AI agents, each a Firecracker microVM, with pause/resume, snapshots and forking.

    • Firecracker microVM
    • Open source
    • Self-hostable
    • BYOC
    • Pause/resume

    Why it’s here: Apache-2.0 SDKs and backend runtime, a single-node self-host package (E2B Embed) with Terraform for AWS, GCP and Azure, and Firecracker isolation. Needs KVM.

    Full profile →E2B alternativesWebsite ↗

  2. Kubernetes Agent Sandbox

    Open-source Kubernetes controller and CRDs for isolated, stateful sandbox pods for AI agents, with first-class support on GKE.

    • gVisor or Kata
    • Open source
    • Self-hostable
    • BYOC
    • GPU
    • Pause/resume

    Why it’s here: Apache-2.0 Kubernetes SIG project with warm pools and CRDs; isolation via gVisor or Kata RuntimeClass. Vendor-neutral and production-oriented.

    Full profile →Website ↗

  3. Microsandbox

    Open-source, local-first microVM runtime that gives each sandbox its own Linux kernel, with an optional managed cloud.

    • MicroVM (libkrun)
    • Open source
    • Self-hostable
    • BYOC
    • Snapshots

    Why it’s here: Apache-2.0 microVM runtime for Linux, macOS and Windows with SDKs in five languages; beta.

    Full profile →Website ↗

  4. Anthropic Sandbox Runtime

    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.

    • OS-level (Seatbelt / bubblewrap)
    • Open source
    • Self-hostable

    Why it’s here: Apache-2.0 OS-level sandbox for local agents and CLIs; lightweight but not a VM boundary.

    Full profile →Website ↗

Side by side

SandboxIsolationOpen sourceSelf-host / BYOCCold start (vendor)Max sessionSnapshots / pauseGPUSDKs
E2BFirecracker microVMYesYes / YesNot documented1 h / 24 h (Pro)Yes / YesNoPython, JavaScript/TypeScript
Kubernetes Agent SandboxgVisor or KataYesYes / Yes<1 s (warm pool)Not documentedYes / YesYesKubernetes CRDs, Python, kubectl
MicrosandboxMicroVM (libkrun)YesYes / Yes<100 msNot documentedYes / Not documentedNoTypeScript, Python, Rust, Go, Ruby, CLI, MCP server
Anthropic Sandbox RuntimeOS-level (Seatbelt / bubblewrap)YesYes / Not documentedProcess startNot documentedNo / NoNot documentedCLI (srt), TypeScript (npm)

Frequently asked questions

Is Daytona still open source?
Daytona archived its public AGPL-3.0 repository in June 2026 and moved core development to a private codebase. The archived code remains available, but it is no longer actively developed in the open.
What is the best open-source alternative to E2B?
Kubernetes Agent Sandbox if you run Kubernetes; Microsandbox for single machines. E2B itself is also open source and self-hostable.

Cite this page

Agent Sandboxes. (2026). Best open-source and self-hosted agent sandboxes. agentsandboxes.org. Last reviewed November 8, 2026. https://agentsandboxes.org/best/open-source/

Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.