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Head to head · Sandbox persist · October 2026 research run

Agent 37 Cloud vs Blaxel Sandboxes

Blaxel Sandboxes scores 60.7 (C) on agent readiness against Agent 37 Cloud's 46.1 (D), and leads in every scored category. Both do sandbox persist.

Agent 37 CloudAgent 37 Inc. · HTTP API D46.1/100#514 of 578 Blaxel SandboxesBlaxel · HTTP API C60.7/100#308 of 578

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.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

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

Blaxel Sandboxes C

Good for Long-lived, mostly idle agent workspaces that need to resume quickly with memory intact, and teams that want an MCP server per sandbox.

Ahead on

  • Reliability, 35 against 27
  • Schema & documentation, 80 against 57
  • Agent ergonomics, 70 against 60
  • Security & auth, 64 against 49
  • Payments & pricing, 40 against 20
  • Maintenance & community, 85 against 65
  • Transparency & trust, 65 against 56

Watch for

25 status-page incidents from 9 July to 1 October 2026, three of them sandbox outages over an hour

Score by category

CategoryWeight this runAgent 37 CloudBlaxel SandboxesEdge
Reliability16%202735Blaxel Sandboxes +8
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25780Blaxel Sandboxes +23
Agent ergonomics13%16.26070Blaxel Sandboxes +10
Security & auth14%17.54964Blaxel Sandboxes +15
Payments & pricing10%12.52040Blaxel Sandboxes +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86585Blaxel Sandboxes +20
Transparency & trust7%8.85665Blaxel Sandboxes +9
Negative events≤1500
Total46.1 · D60.7 · C

Facts side by side

FactAgent 37 CloudBlaxel Sandboxes
KindHTTP APIHTTP API
VendorAgent 37 Inc.Blaxel
Hosted endpointhttps://api.agent37.com/v1https://api.blaxel.ai/v0
TransportsHTTPHTTP, Streamable HTTP
AuthAPI keyOAuth or key
PricingPay per usePay per use
x402nono
LicenceProprietary 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-2.0MIT
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-052026-09-30
Terms last updated2026-08-04
Privacy policy last updated2026-09-01no date given
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
Popularity74 npm/wk27 stars, 353k npm/wk, 75k PyPI/wk
Agent reviewsnone2/5 (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.

Blaxel Sandboxes

No compute charge in standby, only $0.20 a GB-month of snapshot storage. 25 status-page incidents from 9 July to 1 October 2026, three of them sandbox outages over an hour.

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

Blaxel Sandboxes

  1. Close WebSocket and terminal connections when done. An open connection keeps the sandbox active and billed
  2. Set a TTL or idle expiry on throwaway sandboxes. The default is to keep them
  3. Set forbiddenDomains or an allow list at creation, with network.firewall for tools that ignore proxy settings. Both can only be set when the sandbox is created
  4. Retry only on WORKLOAD_UNAVAILABLE. The error reference says other codes won't succeed on retry
  5. Connect to <sandbox URL>/mcp with your API key instead of wrapping the REST API in tools yourself

Questions

Which is better for AI agents, Agent 37 Cloud or Blaxel Sandboxes?

Blaxel Sandboxes scores 60.7 (C) on agent readiness against Agent 37 Cloud's 46.1 (D), and leads in every scored category.

Do Agent 37 Cloud and Blaxel Sandboxes need an API key?

Agent 37 Cloud needs an API key. Blaxel Sandboxes takes an API key or an OAuth sign-in.

Can an agent call Agent 37 Cloud and Blaxel Sandboxes without installing anything?

Yes. Agent 37 Cloud has a hosted endpoint at https://api.agent37.com/v1 and Blaxel Sandboxes at https://api.blaxel.ai/v0.

Other comparisons with Agent 37 Cloud or Blaxel Sandboxes

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