Microsoft eXecution Container (MXC)
MXC is a sandboxed code execution system for running untrusted code
(model output, plugins, and tools) on Windows, Linux, and macOS. It provides
multiple containment backends, from OS-native process sandboxes to full VMs,
behind a unified containment model and typed SDKs.
Features
- Cross-platform: Windows, Linux, and macOS support with
platform-appropriate containment backends
- JSON-based configuration: Versioned container-creation requests and
security policies
- Multiple containment backends: ProcessContainer, Windows Sandbox, LXC,
Bubblewrap, Seatbelt, MicroVM (Nanvix), Hyperlight, IsolationSession, and WSLC
- Policy-driven sandboxing:
- Filesystem policy: Read-only, read-write, and denied path lists
- Network policy: Proxy support, outbound controls, and backend-dependent
host filtering
- UI policy: Clipboard, display, and GUI access controls
- Container lifecycle operations: Provision, start, execute, stop, and deprovision
persistent containers
- Rust, .NET, and Node SDKs: Versioned APIs for create-and-run execution and
container lifecycle operations
- Diagnostics: Tools to understand access-denied failures in a container
What is MXC?
MXC is an SDK dependency that builds into your app.
flowchart LR
App["Your application<br/>Launch API"] --> SDK["MXC SDK<br/>Rust / .NET / Node<br/>(in process)"]
SDK --> Backend["Selected backend<br/>(in process)"]
Backend --> Container["Isolated workload<br/>ProcessContainer / WSLC / Bubblewrap / ..."]
Your application specifies:
- The container type
- The containment rules
- The workload command
MXC validates the request, selects the backend, and launches the workload in
the resulting container.
What container types are supported?
MXC runs workloads through platform-appropriate container backends on Windows,
Linux, and macOS.
| Runtime platform |
Default backend |
Other backends |
Minimum host OS |
| Windows 11 x64 / ARM64 |
processcontainer |
windows_sandbox*, wslc, microvm*, hyperlight*, isolation_session |
Windows OS-version support |
| Linux x64 / ARM64 |
bubblewrap |
lxc, microvm, hyperlight |
- |
| macOS ARM64 / x64 |
seatbelt |
- |
- |
* These backends are experimental.
How do I use MXC?
Install an SDK through your package manager. You do not need to clone this
repository.
The Node and .NET packages include the native runtime assets. The Rust crate
builds the MXC SDK, engine, and selected backends into the consuming
application.
Non-SDK consumption: Platform-specific executor binaries, such as
wxc-exec.exe, accept JSON container-creation requests defined by the
stable schema. Use for testing or when the
SDK cannot be embedded in your app.
Running a contained workload
For complete SDK samples, see the
Rust, .NET, and Node samples.
Sample Node snippet
import { spawn, type ContainerRequest } from '@microsoft/mxc-sdk/v1';
const request: ContainerRequest = {
command: 'node -e "console.log(\'hello from container\')"',
network: { egress: { default: 'deny' } },
timeoutMs: 30_000,
};
const child = await spawn(request);
See the runnable
streaming standard-I/O sample and the
SDK API reference.
My application won't run in the sandbox!
Your application will hit access issues when running in a sandbox, until you've
had time to tune your containment rules. We're here to help.
Debug console mode
Native executors normally reserve standard input, output, and error for the
workload. Use --debug for MXC diagnostic output:
wxc-exec.exe --debug config.json
See MXC diagnostics for the complete
developer reference.
Audit mode
Warning: --audit turns off all sandbox security for the workload being
analyzed. Never use it to run untrusted code.
Audit mode helps a policy author find access-denied failures and reconstruct a
ProcessContainer policy that grants the files and capabilities a trusted tool
actually needs. On supported Windows releases, run:
wxc-exec.exe --audit policy.json
MXC records the observed accesses and produces policy-authoring artifacts. See
logging access denied for safe
deny-and-record diagnostics, audit outputs, and supported workflows.
Telemetry
Official Microsoft builds can send optional diagnostic telemetry to Microsoft.
Telemetry is off unless the individual run opts in, the Windows user has
explicitly consented, administrative policy permits collection, and your
application enables the telemetry option in a contained workload request. An
administrator can block telemetry but cannot grant consent for the user.
Local open-source builds are not configured to route telemetry to Microsoft,
and telemetry is a no-op on non-Windows platforms. See
telemetry policy and consent for controls and privacy
details.
Building from source
Build from source when developing MXC, changing the native runtime, or using
the standalone executor binaries instead of a packaged SDK. Repository builds
produce the platform-native runtime and executors and stage the native assets
used by the Node SDK.
Build prerequisites are:
- Rust, required version 1.93 as specified by
src/rust-toolchain.toml
- Node.js 24 or later and npm
- The platform toolchain and prerequisites described by the selected backend
Build
Windows
build.bat --all # Release build for current architecture
Linux
./build.sh --all # Release build
macOS
./build-mac.sh --all # Release build for native architecture
Documentation
Consumer documentation
Repository contributors should start with the
MXC development documentation.
Contributing
See CONTRIBUTING.md for contribution guidelines.
License
See LICENSE.md for details.
MXC（Microsoft eXecution Container）是一个沙箱化代码执行系统，用于在 Windows、Linux 和 macOS 上运行不受信任的代码——模型输出、插件和工具，其隔离后端涵盖从操作系统原生进程沙箱到完整虚拟机。