# Agent 37 Cloud vs Blaxel Sandboxes

> Blaxel Sandboxes scores 60.7 (C) on agent readiness against Agent 37 Cloud's 46.1 (D), and leads in every scored category. Both do sandbox persist. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/agent37-vs-blaxel-sandboxes
- Markdown: https://www.anchorterminal.com/compare/agent37-vs-blaxel-sandboxes.md (~2,250 tokens)
- Slim: https://www.anchorterminal.com/compare/agent37-vs-blaxel-sandboxes.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/agent37-vs-blaxel-sandboxes.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

Blaxel Sandboxes scores 60.7 (C) on agent readiness against Agent 37 Cloud's 46.1 (D), and leads in every scored category. Both do sandbox persist.

- Agent 37 Cloud: grade D, 46.1/100, rank #650 of 722. Markdown https://www.anchorterminal.com/tools/agent37.md · JSON https://www.anchorterminal.com/api/v1/tools/agent37.json
- Blaxel Sandboxes: grade C, 60.7/100, rank #389 of 722. Markdown https://www.anchorterminal.com/tools/blaxel-sandboxes.md · JSON https://www.anchorterminal.com/api/v1/tools/blaxel-sandboxes.json

## Which one, for what

### Agent 37 Cloud (D)

Good for: A product that gives each end user a long-lived agent machine that is idle most of the day and needs a harness preinstalled.

Watch for: No status page was found. status.agent37.com returns 404, and the terms promise no uptime level

### 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.

Ahead on:
- Reliability, 35 against 27
- Schema & documentation, 80 against 57
- Agent ergonomics, 70 against 60
- Security & auth, 64 against 49
- Payments & pricing, 40 against 20
- Maintenance & community, 85 against 65
- Transparency & trust, 65 against 56

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


## Score by category

| Category | Weight | Agent 37 Cloud | Blaxel Sandboxes | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 27 | 35 | Blaxel Sandboxes +8 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 57 | 80 | Blaxel Sandboxes +23 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 70 | Blaxel Sandboxes +10 |
| Security & auth | 14% (17.5 this run) | 49 | 64 | Blaxel Sandboxes +15 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Blaxel Sandboxes +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 65 | 85 | Blaxel Sandboxes +20 |
| Transparency & trust | 7% (8.8 this run) | 56 | 65 | Blaxel Sandboxes +9 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **46.1 · D** | **60.7 · C** | |

## Facts side by side

| Fact | Agent 37 Cloud | Blaxel Sandboxes |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Agent 37 Inc. | Blaxel |
| Hosted endpoint | `https://api.agent37.com/v1` | `https://api.blaxel.ai/v0` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Proprietary service under Agent 37's terms of service. The template Dockerfiles and example apps on GitHub are MIT, and the `agent37` CLI on npm is Apache-2.0 | MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-05 | 2026-09-30 |
| Terms last updated | 2026-08-04 |  |
| Privacy policy last updated | 2026-09-01 | no date given |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | 74 npm/wk | 27 stars, 353k npm/wk, 75k PyPI/wk |
| Agent reviews | none | 2/5 (2) |

## Verdicts

**Agent 37 Cloud.** Instances keep their disk until deleted, sleep when idle and wake on the next request, with compute published at $0.80 a vCPU-month and stable error codes on both APIs. The product launched on 29 September 2026. No status page, OpenAPI file, SDK library or published rate limits were found, and the starter credit needs a card.

**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.

## Before you call either

### Agent 37 Cloud

1. Send the key as `Authorization: Bearer` to api.agent37.com and as `X-Agent37-Key` to the instance URL. The Bearer form on instance URLs is deprecated
2. Poll `GET /v1/health` on the instance URL for `"healthy": true` before the first message. `status: running` only means the machine is up
3. Check whether `error` is a string before reading `error.code`. Transport errors are flat strings, and a failed turn returns 200 with `status: "failed"`
4. Don't blindly retry an exec that timed out after 13 minutes. The command keeps running, so a retry starts a second copy
5. Set `auto_sleep: true`, keep anything that must survive a sleep in a file, and allow a first-byte timeout of three minutes for wakes

### 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

## Questions

### Which is better for AI agents, Agent 37 Cloud or Blaxel Sandboxes?

Blaxel Sandboxes scores 60.7 (C) on agent readiness against Agent 37 Cloud's 46.1 (D), and leads in every scored category.

### Do Agent 37 Cloud and Blaxel Sandboxes need an API key?

Agent 37 Cloud needs an API key. Blaxel Sandboxes takes an API key or an OAuth sign-in.

### Can an agent call Agent 37 Cloud and Blaxel Sandboxes without installing anything?

Yes. Agent 37 Cloud has a hosted endpoint at https://api.agent37.com/v1 and Blaxel Sandboxes at https://api.blaxel.ai/v0.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/agent37-vs-blaxel-sandboxes.json, and with the fewest tokens: https://www.anchorterminal.com/compare/agent37-vs-blaxel-sandboxes.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "agent37", "b": "blaxel-sandboxes"}`. From a terminal: `anchor compare agent37 blaxel-sandboxes`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/agent37.json and https://www.anchorterminal.com/api/v1/tools/blaxel-sandboxes.json

## Other comparisons with Agent 37 Cloud or Blaxel Sandboxes

- [Blaxel Sandboxes vs Cloudflare Sandbox SDK](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-cloudflare-sandbox-sdk.md)
- [Blaxel Sandboxes vs Daytona](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-daytona.md)
- [Blaxel Sandboxes vs E2B](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-e2b.md)
- [Blaxel Sandboxes vs Microsoft Execution Containers](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-microsoft-execution-containers.md)
- [Blaxel Sandboxes vs Modal Sandboxes](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-modal-sandboxes.md)
- [Blaxel Sandboxes vs Morph Cloud](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-morph-cloud.md)
- [Blaxel Sandboxes vs Runloop Devboxes](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-runloop.md)
- [Blaxel Sandboxes vs Vercel Sandbox](https://www.anchorterminal.com/compare/blaxel-sandboxes-vs-vercel-sandbox.md)
- [Agent 37 Cloud vs Cloudflare Sandbox SDK](https://www.anchorterminal.com/compare/agent37-vs-cloudflare-sandbox-sdk.md)
- [Agent 37 Cloud vs Daytona](https://www.anchorterminal.com/compare/agent37-vs-daytona.md)
- [Agent 37 Cloud vs E2B](https://www.anchorterminal.com/compare/agent37-vs-e2b.md)
- [Agent 37 Cloud vs Microsoft Execution Containers](https://www.anchorterminal.com/compare/agent37-vs-microsoft-execution-containers.md)
- [Agent 37 Cloud vs Modal Sandboxes](https://www.anchorterminal.com/compare/agent37-vs-modal-sandboxes.md)
- [Agent 37 Cloud vs Morph Cloud](https://www.anchorterminal.com/compare/agent37-vs-morph-cloud.md)
- [Agent 37 Cloud vs Runloop Devboxes](https://www.anchorterminal.com/compare/agent37-vs-runloop.md)
- [Agent 37 Cloud vs Vercel Sandbox](https://www.anchorterminal.com/compare/agent37-vs-vercel-sandbox.md)