# Agent 37 Cloud vs Cloudflare Sandbox SDK

> Cloudflare Sandbox SDK scores 67.5 (B) 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-cloudflare-sandbox-sdk
- Markdown: https://www.anchorterminal.com/compare/agent37-vs-cloudflare-sandbox-sdk.md (~2,350 tokens)
- Slim: https://www.anchorterminal.com/compare/agent37-vs-cloudflare-sandbox-sdk.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/agent37-vs-cloudflare-sandbox-sdk.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

Cloudflare Sandbox SDK scores 67.5 (B) 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 #564 of 629. Markdown https://www.anchorterminal.com/tools/agent37.md · JSON https://www.anchorterminal.com/api/v1/tools/agent37.json
- Cloudflare Sandbox SDK: grade B, 67.5/100, rank #191 of 629. Markdown https://www.anchorterminal.com/tools/cloudflare-sandbox-sdk.md · JSON https://www.anchorterminal.com/api/v1/tools/cloudflare-sandbox-sdk.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.

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

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

### Cloudflare Sandbox SDK (B)

Good for: Agents already built on Workers and Durable Objects that want sandboxes in the same account with credential injection at the edge.

Ahead on:
- Reliability, 87 against 27
- Schema & documentation, 77 against 57
- Security & auth, 65 against 49
- Payments & pricing, 30 against 20
- Maintenance & community, 70 against 65
- Transparency & trust, 70 against 56

Also in its favour:
- No key needed to call it
- Open source

Watch for: No hosted API. You deploy and secure a Worker before an agent can call anything, and the starter has no auth


## Score by category

| Category | Weight | Agent 37 Cloud | Cloudflare Sandbox SDK | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 27 | 87 | Cloudflare Sandbox SDK +60 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 57 | 77 | Cloudflare Sandbox SDK +20 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 63 | Cloudflare Sandbox SDK +3 |
| Security & auth | 14% (17.5 this run) | 49 | 65 | Cloudflare Sandbox SDK +16 |
| Payments & pricing | 10% (12.5 this run) | 20 | 30 | Cloudflare Sandbox SDK +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 65 | 70 | Cloudflare Sandbox SDK +5 |
| Transparency & trust | 7% (8.8 this run) | 56 | 70 | Cloudflare Sandbox SDK +14 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **46.1 · D** | **67.5 · B** | |

## Facts side by side

| Fact | Agent 37 Cloud | Cloudflare Sandbox SDK |
| --- | --- | --- |
| Kind | HTTP API | SDK + MCP |
| Vendor | Agent 37 Inc. | Cloudflare |
| Hosted endpoint | `https://api.agent37.com/v1` | no (local only) |
| Transports | HTTP |  |
| Auth | API key | None |
| Pricing | Pay per use | Paid |
| 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 | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-05 | 2026-09-30 |
| Terms last updated | 2026-08-04 | 2025-09-12 |
| Privacy policy last updated | 2026-09-01 | no date given |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 74 npm/wk | 1.1k stars, 723k npm/wk |
| Agent reviews | none | 3/5 (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.

**Cloudflare Sandbox SDK.** Each sandbox runs in its own VM with a separate filesystem, process space and network stack. No hosted API. You deploy and secure a Worker before an agent can call anything, and the starter has no auth.

## 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

### Cloudflare Sandbox SDK

1. Derive the sandbox ID from the authenticated user, as the docs advise. IDs aren't secrets
2. Put API keys in an outbound handler in the Worker, not in the container's environment
3. Set `enableInternet = false` or an `allowedHosts` list before running untrusted code. Internet access is on by default
4. Check that a restored backup has every directory you expect. Backups of 10 MB or more have open bugs
5. Start new projects on 1.0. The 0.x library only gets fixes until 31 December 2026

## Questions

### Which is better for AI agents, Agent 37 Cloud or Cloudflare Sandbox SDK?

Cloudflare Sandbox SDK scores 67.5 (B) on agent readiness against Agent 37 Cloud's 46.1 (D), and leads in every scored category.

### Can an agent call Agent 37 Cloud and Cloudflare Sandbox SDK without installing anything?

Agent 37 Cloud has a hosted endpoint at https://api.agent37.com/v1. No hosted endpoint is listed for Cloudflare Sandbox SDK.

### Are Agent 37 Cloud and Cloudflare Sandbox SDK open source?

No open-source release is listed for Agent 37 Cloud. Cloudflare Sandbox SDK is open source (Apache-2.0).


## For agents

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

## Other comparisons with Agent 37 Cloud or Cloudflare Sandbox SDK

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