# Cloudflare Sandbox SDK vs Freestyle

> Cloudflare Sandbox SDK scores 67.5 (B) on agent readiness against Freestyle's 58.5 (C), and leads in 3 of 7 scored categories. Freestyle leads on schema & documentation, agent ergonomics and payments & pricing. Both do sandbox code. Category scores, facts, verdicts and agent…

- Canonical: https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-freestyle
- Markdown: https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-freestyle.md (~2,600 tokens)
- Slim: https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-freestyle.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/cloudflare-sandbox-sdk-vs-freestyle.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 Freestyle's 58.5 (C), and leads in 3 of 7 scored categories. Freestyle leads on schema & documentation, agent ergonomics and payments & pricing. 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
- Freestyle: grade C, 58.5/100, rank #520 of 842. Markdown https://www.anchorterminal.com/tools/freestyle.md · JSON https://www.anchorterminal.com/api/v1/tools/freestyle.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 43
- Security & auth, 65 against 53
- Transparency & trust, 70 against 41

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

### Freestyle (C)

Good for: Suited to long-running agent work that needs a full Linux VM, memory-preserving pause, snapshots to branch from and private networking.

Ahead on:
- Schema & documentation, 86 against 77
- Agent ergonomics, 69 against 63
- Payments & pricing, 45 against 30

Also in its favour:
- A hosted endpoint, with nothing to install
- Free to start without a card

Watch for: No terms of service or service agreement found on the site, and the privacy policy covers the website only


## Score by category

| Category | Weight | Cloudflare Sandbox SDK | Freestyle | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 87 | 43 | Cloudflare Sandbox SDK +44 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 77 | 86 | Freestyle +9 |
| Agent ergonomics | 13% (16.2 this run) | 63 | 69 | Freestyle +6 |
| Security & auth | 14% (17.5 this run) | 65 | 53 | Cloudflare Sandbox SDK +12 |
| Payments & pricing | 10% (12.5 this run) | 30 | 45 | Freestyle +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 70 | 71 | Freestyle +1 |
| Transparency & trust | 7% (8.8 this run) | 70 | 41 | Cloudflare Sandbox SDK +29 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **67.5 · B** | **58.5 · C** | |

## Facts side by side

| Fact | Cloudflare Sandbox SDK | Freestyle |
| --- | --- | --- |
| Kind | SDK + MCP | HTTP API |
| Vendor | Cloudflare | Freestyle Cloud Inc. |
| Hosted endpoint | no (local only) | `https://api.freestyle.sh/v5` |
| Transports |  | HTTP |
| Auth | None | API key |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary service with no published terms of service found. The `freestyle` SDK and CLI package on npm is MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-30 | 2026-09-27 |
| Terms last updated | 2025-09-12 | no document linked |
| Privacy policy last updated | no date given | no document linked |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | 1.1k stars, 723k npm/wk | 72k npm/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.

**Freestyle.** A public OpenAPI 3.1 file describes 88 operations with a stable error code on every failure, and per-VM identity tokens keep the team API key away from end users. No terms of service, product privacy policy, request rate limit or incident history was found, and the only SDK is TypeScript.

## 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

### Freestyle

1. Send a `firewall` object on every `POST /v5/vms`. It is required, and a VM with no rules has no outbound internet
2. Ask the owner to run `freestyle login` in a browser once, then mint a key with `freestyle tokens create --output json`
3. Do not retry an exec that answers 409 `VM_NON_RESPONSIVE`. The command may already have run
4. Keep `exec-await` under its 300,000 ms cap and use a PTY session or `x-freestyle-background-after-secs` for longer work
5. Call the `/v5` paths. The unversioned duplicates in the OpenAPI file are marked deprecated

## Questions

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

Cloudflare Sandbox SDK scores 67.5 (B) on agent readiness against Freestyle's 58.5 (C), and leads in 3 of 7 scored categories. Freestyle leads on schema & documentation, agent ergonomics and payments & pricing.

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

No hosted endpoint is listed for Cloudflare Sandbox SDK. Freestyle has a hosted endpoint at https://api.freestyle.sh/v5.

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

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


## For agents

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

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