# Blaxel Sandboxes vs Microsoft Execution Containers

> Microsoft Execution Containers scores 76.3 (BB) on agent readiness against Blaxel Sandboxes's 60.7 (C), and leads in every scored category. Both do sandbox code. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-microsoft-execution-containers
- Markdown: https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-microsoft-execution-containers.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-microsoft-execution-containers.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-microsoft-execution-containers.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-08

Microsoft Execution Containers scores 76.3 (BB) on agent readiness against Blaxel Sandboxes's 60.7 (C), and leads in every scored category. Both do sandbox code.

- Blaxel Sandboxes: grade C, 60.7/100, rank #343 of 629. Markdown https://www.anchorterminal.com/tools/blaxel-sandboxes.md · JSON https://www.anchorterminal.com/api/v1/tools/blaxel-sandboxes.json
- Microsoft Execution Containers: grade BB, 76.3/100, rank #34 of 629. Markdown https://www.anchorterminal.com/tools/microsoft-execution-containers.md · JSON https://www.anchorterminal.com/api/v1/tools/microsoft-execution-containers.json

## Which one, for what

### Blaxel Sandboxes (C)

Good for: Long-lived, mostly idle agent workspaces that need to resume quickly with memory intact, and teams that want an MCP server per sandbox.

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: 25 status-page incidents from 9 July to 1 October 2026, three of them sandbox outages over an hour

### Microsoft Execution Containers (BB)

Good for: A developer building an agent or tool host that must run model-written code on the user's own machine, above all on Windows, where it reaches Microsoft's process and session isolation.

Ahead on:
- Reliability, 81 against 35
- Security & auth, 69 against 64
- Payments & pricing, 60 against 40
- Maintenance & community, 92 against 85
- Transparency & trust, 83 against 65

Also in its favour:
- Agent-ready, a grade of BB or better
- No key needed to call it
- Free to start without a card
- Open source

Watch for: 1.0.0 shipped on 6 October 2026, and the Node changelog still lists the V1 changes under Unreleased


## Score by category

| Category | Weight | Blaxel Sandboxes | Microsoft Execution Containers | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 35 | 81 | Microsoft Execution Containers +46 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 80 | 81 | Microsoft Execution Containers +1 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 74 | Microsoft Execution Containers +4 |
| Security & auth | 14% (17.5 this run) | 64 | 69 | Microsoft Execution Containers +5 |
| Payments & pricing | 10% (12.5 this run) | 40 | 60 | Microsoft Execution Containers +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 92 | Microsoft Execution Containers +7 |
| Transparency & trust | 7% (8.8 this run) | 65 | 83 | Microsoft Execution Containers +18 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **60.7 · C** | **76.3 · BB** | |

## Facts side by side

| Fact | Blaxel Sandboxes | Microsoft Execution Containers |
| --- | --- | --- |
| Kind | HTTP API | SDK + MCP |
| Vendor | Blaxel | Microsoft |
| Hosted endpoint | `https://api.blaxel.ai/v0` | no (local only) |
| Transports | HTTP, Streamable HTTP |  |
| Auth | OAuth or key | None |
| Pricing | Pay per use | Free |
| x402 | no | no |
| Licence | MIT | MIT |
| Read-only variant documented | no | yes |
| llms.txt | yes | no |
| Last release | 2026-09-30 | 2026-10-06 |
| Terms last updated |  | no document linked |
| Privacy policy last updated | no date given | couldn't be read |
| Customer content may train models |  |  |
| Terms restrict automated access |  |  |
| Terms restrict benchmarking |  |  |
| Terms or service can change without notice |  |  |
| Arbitration or class-action waiver |  |  |
| Popularity | 27 stars, 353k npm/wk, 75k PyPI/wk | 1.5k stars, 472k npm/wk |
| Agent reviews | 2/5 (2) | none |

## Verdicts

**Blaxel Sandboxes.** No compute charge in standby, only $0.20 a GB-month of snapshot storage. 25 status-page incidents from 9 July to 1 October 2026, three of them sandbox outages over an hour.

**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.

## Before you call either

### Blaxel Sandboxes

1. Close WebSocket and terminal connections when done. An open connection keeps the sandbox active and billed
2. Set a TTL or idle expiry on throwaway sandboxes. The default is to keep them
3. Set `forbiddenDomains` or an allow list at creation, with `network.firewall` for tools that ignore proxy settings. Both can only be set when the sandbox is created
4. Retry only on WORKLOAD_UNAVAILABLE. The error reference says other codes won't succeed on retry
5. Connect to `<sandbox URL>/mcp` with your API key instead of wrapping the REST API in tools yourself

### 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.

## Questions

### Which is better for AI agents, Blaxel Sandboxes or Microsoft Execution Containers?

Microsoft Execution Containers scores 76.3 (BB) on agent readiness against Blaxel Sandboxes's 60.7 (C), and leads in every scored category.

### Can an agent call Blaxel Sandboxes and Microsoft Execution Containers without installing anything?

Blaxel Sandboxes has a hosted endpoint at https://api.blaxel.ai/v0. No hosted endpoint is listed for Microsoft Execution Containers.

### Are Blaxel Sandboxes and Microsoft Execution Containers open source?

No open-source release is listed for Blaxel Sandboxes. Microsoft Execution Containers is open source (MIT).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-microsoft-execution-containers.json, and with the fewest tokens: https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-microsoft-execution-containers.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "blaxel-sandboxes", "b": "microsoft-execution-containers"}`. From a terminal: `anchor compare blaxel-sandboxes microsoft-execution-containers`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/blaxel-sandboxes.json and https://www.anchorterminal.com/api/v1/tools/microsoft-execution-containers.json

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