# Freestyle vs Modal Sandboxes

> Modal Sandboxes scores 75.5 (BB) on agent readiness against Freestyle's 58.5 (C), and leads in 4 of 7 scored categories. Freestyle leads on schema & documentation and payments & pricing. Both do sandbox code. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/freestyle-vs-modal-sandboxes
- Markdown: https://www.anchorterminal.com/compare/freestyle-vs-modal-sandboxes.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/freestyle-vs-modal-sandboxes.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/freestyle-vs-modal-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: 2026-10-09

Modal Sandboxes scores 75.5 (BB) on agent readiness against Freestyle's 58.5 (C), and leads in 4 of 7 scored categories. Freestyle leads on schema & documentation and payments & pricing. Both do sandbox code.

- 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
- Modal Sandboxes: grade BB, 75.5/100, rank #45 of 842. Markdown https://www.anchorterminal.com/tools/modal-sandboxes.md · JSON https://www.anchorterminal.com/api/v1/tools/modal-sandboxes.json

## Which one, for what

### 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 79
- Payments & pricing, 45 against 40

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

### Modal Sandboxes (BB)

Good for: GPU work inside a sandbox, or agents already running on Modal.

Ahead on:
- Reliability, 95 against 43
- Security & auth, 76 against 53
- Maintenance & community, 93 against 71
- Transparency & trust, 72 against 41

Also in its favour:
- Agent-ready, a grade of BB or better

Watch for: No REST API, and the JavaScript and Go SDKs are beta


## Score by category

| Category | Weight | Freestyle | Modal Sandboxes | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 43 | 95 | Modal Sandboxes +52 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 86 | 79 | Freestyle +7 |
| Agent ergonomics | 13% (16.2 this run) | 69 | 67 | Freestyle +2 |
| Security & auth | 14% (17.5 this run) | 53 | 76 | Modal Sandboxes +23 |
| Payments & pricing | 10% (12.5 this run) | 45 | 40 | Freestyle +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 71 | 93 | Modal Sandboxes +22 |
| Transparency & trust | 7% (8.8 this run) | 41 | 72 | Modal Sandboxes +31 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **58.5 · C** | **75.5 · BB** | |

## Facts side by side

| Fact | Freestyle | Modal Sandboxes |
| --- | --- | --- |
| Kind | HTTP API | SDK + MCP |
| Vendor | Freestyle Cloud Inc. | Modal |
| Hosted endpoint | `https://api.freestyle.sh/v5` | no (local only) |
| Transports | HTTP |  |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service with no published terms of service found. The `freestyle` SDK and CLI package on npm is MIT | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-27 | 2026-09-28 |
| Terms last updated | no document linked | 2026-05-01 |
| Privacy policy last updated | no document linked | 2023-05-17 |
| 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 | 72k npm/wk | 514 stars, 941k npm/wk, 10.1M PyPI/wk |
| Agent reviews | none | 3.3/5 (8) |

## Verdicts

**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.

**Modal Sandboxes.** GPU sandboxes at the same per-second rates as the rest of Modal. No REST API, and the JavaScript and Go SDKs are beta.

## Before you call either

### 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

### Modal Sandboxes

1. Pass `timeout=` when you create a sandbox. The default lifetime is 5 minutes
2. Set `block_network=True` or a `cidr_allowlist` for untrusted code
3. Give a sandbox a `name` so a retried create raises `AlreadyExistsError` instead of starting a second one
4. Snapshot the filesystem before the 24-hour limit and start a fresh sandbox from it
5. Catch `ResourceExhaustedError` from `Sandbox.create()` on SDK 1.6.0 and later

## Questions

### Which is better for AI agents, Freestyle or Modal Sandboxes?

Modal Sandboxes scores 75.5 (BB) on agent readiness against Freestyle's 58.5 (C), and leads in 4 of 7 scored categories. Freestyle leads on schema & documentation and payments & pricing.

### Can an agent call Freestyle and Modal Sandboxes without installing anything?

Freestyle has a hosted endpoint at https://api.freestyle.sh/v5. No hosted endpoint is listed for Modal Sandboxes.


## For agents

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

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