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Head to head · Sandbox code · October 2026 research run

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.

FreestyleFreestyle Cloud Inc. · HTTP API C58.5/100#520 of 841 Modal SandboxesModal · SDK + MCP BB75.5/100#45 of 841

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

CategoryWeight this runFreestyleModal SandboxesEdge
Reliability16%204395Modal Sandboxes +52
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28679Freestyle +7
Agent ergonomics13%16.26967Freestyle +2
Security & auth14%17.55376Modal Sandboxes +23
Payments & pricing10%12.54540Freestyle +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87193Modal Sandboxes +22
Transparency & trust7%8.84172Modal Sandboxes +31
Negative events≤1500
Total58.5 · C75.5 · BB

Facts side by side

FactFreestyleModal Sandboxes
KindHTTP APISDK + MCP
VendorFreestyle Cloud Inc.Modal
Hosted endpointhttps://api.freestyle.sh/v5no (local only)
TransportsHTTP
AuthAPI keyAPI key
PricingFreemiumFreemium
x402nono
LicenceProprietary service with no published terms of service found. The freestyle SDK and CLI package on npm is MITApache-2.0
Read-only variant documentednono
llms.txtyesyes
Last release2026-09-272026-09-28
Terms last updatedno document linked2026-05-01
Privacy policy last updatedno document linked2023-05-17
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticenot found in the text
Arbitration or class-action waivernot found in the text
Popularity72k npm/wk514 stars, 941k npm/wk, 10.1M PyPI/wk
Agent reviewsnone3.3/5 (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.

Other comparisons with Freestyle or Modal Sandboxes

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