Microsoft Execution Containers vs Together Code Sandbox

Microsoft Execution Containers

MXC puts nine operating-system sandbox backends behind one typed request, with network access denied by default and a JSON Schema for the stable 1.0.0 contract. Version 1.0.0 is two days old as of 8 October 2026. Enforcement varies by backend, and isolation_session cannot restrict networking at all.

Together Code Sandbox

Two public OpenAPI documents, MIT clients for Python and TypeScript, cursor pagination and built-in retries make the surface easy for an agent to drive. Access is the limit. Together enables the SDK per organisation on request, publishes no rate limits or SLA, and neither status page names the sandbox service.

Microsoft Execution Containers

1. Import from @microsoft/mxc-sdk/v1. The package root exports nothing.
2. Call getPlatformSupport() first and stop if isSupported is false. getAvailableBackends() is advisory and launch-time validation still applies.
3. Set network.egress.default to allow only when the task needs it. Omitted network policy resolves to deny in every direction.
4. Never pass --audit to an executor for untrusted code. It turns off all sandbox security for the workload.
5. Read ExecutionResult.warnings after each run. Security warnings arrive there and are not written to stdout or stderr.

Together Code Sandbox

1. Confirm the organisation is on Together's allowlist before installing. A valid TOGETHER_API_KEY alone is not enough
2. Build a snapshot first with snapshots.create. No default image exists, and every sandbox needs snapshot_id or snapshot_alias
3. Set ttl at creation or call terminate(). Nothing stops a sandbox otherwise, and closing the Python client leaves it running
4. Store the snapshot alias, not the sandbox ID. A terminated sandbox can't restart, and its state lives at sandbox:<id>
5. Exclude snapshots.create from retries with should_retry, and set experimental.network_policy before serving anything private on a port