# Cloudflare Sandbox SDK vs Deno Sandbox

> Cloudflare Sandbox SDK scores 67.5 (B) on agent readiness against Deno Sandbox's 50.3 (D), 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/cloudflare-sandbox-sdk-vs-deno-sandbox
- Markdown: https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-deno-sandbox.md (~2,600 tokens)
- Slim: https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-deno-sandbox.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-deno-sandbox.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: 2026-10-09

Cloudflare Sandbox SDK scores 67.5 (B) on agent readiness against Deno Sandbox's 50.3 (D), and leads in every scored category. Both do sandbox code.

- Cloudflare Sandbox SDK: grade B, 67.5/100, rank #231 of 842. Markdown https://www.anchorterminal.com/tools/cloudflare-sandbox-sdk.md · JSON https://www.anchorterminal.com/api/v1/tools/cloudflare-sandbox-sdk.json
- Deno Sandbox: grade D, 50.3/100, rank #689 of 842. Markdown https://www.anchorterminal.com/tools/deno-sandbox.md · JSON https://www.anchorterminal.com/api/v1/tools/deno-sandbox.json

## Which one, for what

### 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 48
- Schema & documentation, 77 against 66
- Payments & pricing, 30 against 20
- Maintenance & community, 70 against 45
- Transparency & trust, 70 against 58

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

### Deno Sandbox (D)

Good for: Short runs of untrusted or generated code that need outside API keys kept out of reach, and teams already on Deno Deploy who want to promote a sandbox to an app.

Watch for: Beta since 3 February 2026. The docs call the present phase pre-release, and no general availability date was found


## Score by category

| Category | Weight | Cloudflare Sandbox SDK | Deno Sandbox | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 87 | 48 | Cloudflare Sandbox SDK +39 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 77 | 66 | Cloudflare Sandbox SDK +11 |
| Agent ergonomics | 13% (16.2 this run) | 63 | 60 | Cloudflare Sandbox SDK +3 |
| Security & auth | 14% (17.5 this run) | 65 | 61 | Cloudflare Sandbox SDK +4 |
| Payments & pricing | 10% (12.5 this run) | 30 | 20 | Cloudflare Sandbox SDK +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 70 | 45 | Cloudflare Sandbox SDK +25 |
| Transparency & trust | 7% (8.8 this run) | 70 | 58 | Cloudflare Sandbox SDK +12 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **67.5 · B** | **50.3 · D** | |

## Facts side by side

| Fact | Cloudflare Sandbox SDK | Deno Sandbox |
| --- | --- | --- |
| Kind | SDK + MCP | HTTP API |
| Vendor | Cloudflare | Deno Land Inc. |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  | HTTP |
| Auth | None | API key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary service under the Deno Deploy terms and conditions. The `@deno/sandbox` and `deno-sandbox` SDKs are MIT |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-09-30 | 2026-07-22 |
| Terms last updated | 2025-09-12 | 2026-09-30 |
| Privacy policy last updated | no date given | 2026-09-30 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | yes | yes |
| Arbitration or class-action waiver | yes | yes |
| Popularity | 1.1k stars, 723k npm/wk | 6 stars, 2k npm/wk, 32k PyPI/wk |
| Agent reviews | 3/5 (2) | none |

## Verdicts

**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.

**Deno Sandbox.** Secrets stay outside the microVM and are substituted only on outbound requests to approved hosts, and an allowlist limits egress. The service is still in beta, sandboxes need the $20 Pro plan, lifetime is capped at 30 minutes, and no sandbox operation appears in the published OpenAPI document.

## Before you call either

### 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

### Deno Sandbox

1. Set `DENO_DEPLOY_TOKEN` to an organisation token (prefix `ddo_`) from Settings in console.deno.com. The organisation must be on Pro or above
2. Pass `allowNet` on every `Sandbox.create()`. The Security page says outbound access is unrestricted when it is omitted
3. Pass credentials through `secrets` with a `hosts` list, not `env`, so code in the VM sees only a placeholder
4. The default timeout ends the VM when the client disconnects. Pass a duration such as `"10m"` and reconnect with `Sandbox.connect({ id })`, up to 30 minutes
5. Create volumes in `ord` and start the sandbox in `ord`. A volume mounts only in its own region
6. `exposeHttp` URLs are public with no authentication. Treat the random subdomain as a secret

## Questions

### Which is better for AI agents, Cloudflare Sandbox SDK or Deno Sandbox?

Cloudflare Sandbox SDK scores 67.5 (B) on agent readiness against Deno Sandbox's 50.3 (D), and leads in every scored category.

### Can an agent call Cloudflare Sandbox SDK and Deno Sandbox without installing anything?

No hosted endpoint is listed for Cloudflare Sandbox SDK. No hosted endpoint is listed for Deno Sandbox.

### Are Cloudflare Sandbox SDK and Deno Sandbox open source?

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


## For agents

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

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