Head to head · Persistent sandboxes · October 2026 research run

Agent 37 Cloud vs InstaVM

Agent 37 Cloud scores 53.9 (D) on agent readiness against InstaVM's 52.1 (D), and leads in 5 of 7 scored categories. InstaVM leads on reliability and schema & documentation. Both do persistent sandboxes.

Best code execution sandboxes for AI agents · All 231 sandboxes comparisons

Which one, for what

Agent 37 Cloud D

Best 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.

Ahead on

  • Agent ergonomics, 60 against 51
  • Security & auth, 48 against 41
  • Payments & pricing, 30 against 20
  • Maintenance & community, 65 against 35
  • Transparency & trust, 64 against 57

Watch for

The status page is new, with history only from October 2026, and the terms promise no uptime level

InstaVM D

Best for Hosted microVM sandboxes with browser, desktop, OCI images, clones and public shares.

Ahead on

  • Reliability, 77 against 57
  • Schema & documentation, 66 against 57

Watch for

The free plan's $50 credit needs a card on file, and signup is in a browser

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Maintenance & community Agent 37 Cloud +30

Agent 37 Cloud 65

Scored on the closed-service scale. The newest template image tag is b2b-hermes/2026.11.01a (Hermes v0.22.5), four days before the check (30). The repository holds 77 dated image tags for the API's system templates (14 more are for the Personal Agents app), on 16 days from 2 October to 1 November 2026, each pushed by the publish script for a commit that names the change (20). No public changelog. Support is by email, a dashboard chat and a founder's booking link, and we couldn't read GitHub issues (5 of 15). No SDK library. The agent37 CLI on npm was at 0.4.0 per the 8 October check, not re-read on 5 November, and langchain-agent37 0.1.0 was tagged on 26 October (5 of 15). The templates repository has a test workflow, whose results we couldn't read (5 of 10). Total 65.

InstaVM 35

Closed service lines. The latest dated change found is Python SDK 0.26.1 on 15 July 2026, 114 days before the check, and the site changelog's only entry is 11 July (10). No SDK release in the 90 days to 6 November (0). A public changelog, support email and Discord, with no reply times seen (8 of 15). Official Python and JavaScript SDKs, last released in July and May 2026 (12 of 15). Package health of the SDK repositories was not read (5 of 10). Total 35.

Reliability InstaVM +20

Agent 37 Cloud 57

Graded as a hosted service. A Better Stack status page now answers at status.agent37.com, with components for the website and dashboard, the API, sandbox creation, sandbox URLs and three regions (20). It did not exist on 8 October, when the host answered 404, so the record is short. Its feed lists two incidents, both partial: on 20 October fewer than 1 per cent of US sandboxes restarted (21 minutes degraded), and on 29 October some sandbox creations failed from 14:55 to 16:00 UTC while running sandboxes were not affected. A short record with minor incidents only (15). No request rate limits are published. The only numbers are one on-demand backup per instance every 15 minutes, three concurrent template builds and 20 feedback reports a day (0). Retry guidance is written per code, with backoff for try_again, no_capacity and 429, a Retry-After header on the backup limit, an idempotency key on budget top-ups and a warning that a timed-out exec keeps running, but instance create and exec take no idempotency key (12 of 15). The terms promise no uptime level unless agreed in writing (0). The Cloud API carries no beta label (10). Total 57.

InstaVM 77

Hosted lines. Better Stack status page with four components, including the public API (20). The incident history shows no incidents for September, October or November 2026 (30). No rate limits with numbers found; Pro promises higher limits without figures (0). The Python SDK has a RateLimitError and an example retry loop with exponential backoff, but no 429 or Retry-After is documented, and there is no idempotency guidance (7 of 15). The terms commit to 99.9% monthly uptime with service credits, and Pro lists 99.9% (10). No beta or preview label on the API (10). Total 77.

Payments & pricing Agent 37 Cloud +10

Agent 37 Cloud 30

No x402, MPP or L402 on the API (0). Per-unit prices for vCPU, memory and disk are published without login (20). The one-time $5 credit is granted only after a card is added in the dashboard, and accounts created by API get no credit, so there is no free tier without a card (0). POST /v1/signup, unauthenticated, now creates a workspace and returns a full API key and a Stripe Checkout link, and POST /v1/billing/top-up mints further links. Nothing runs until someone pays that link, so a person completes the step that makes access useful (10 of 20). Total 30.

InstaVM 20

No x402, MPP or L402 (0 of 40). Per-second vCPU, memory and storage prices are published without a login (20). The free plan's $50 credit needs a card on file (0). Signup and key minting are in a browser dashboard (0). Total 20.

Schema & documentation InstaVM +9

Agent 37 Cloud 57

No OpenAPI or other machine-readable contract is shown or linked, and the 794 KB llms-full.txt never mentions one (0). llms.txt now lists 84 pages, with llms-full.txt and a Markdown copy of every page (10). Pages say what each call is for and when to choose another, such as stop against delete, resize against fork and exec for anything unwrapped (17). Parameters are documented with types, ranges, defaults and patterns in prose, with no schema to validate against (10). Curl, Python and JavaScript examples with responses on each page, and an error reference for the Hosting API, transport failures and the Agent API (15). The path is versioned at /v1 and template images carry immutable dated tags, but no public changelog was found (5). Total 57.

InstaVM 66

A public OpenAPI 3.1 spec with 229 operations (25). llms.txt at instavm.io (10). Only 93 of 229 operations have a description, and those read as short summaries without when-not-to-use guidance (8 of 20). FastAPI-generated request schemas with typed fields and required lists (10 of 15). Docs carry code examples for each SDK area, but only 422 validation errors appear in the spec and no error-code reference was found (6 of 15). Paths sit under /v1 and an SDK changelog exists, but the site changelog has one entry, of 11 July 2026 (7 of 15). Total 66.

Agent ergonomics Agent 37 Cloud +9

Agent 37 Cloud 60

Exec output is capped at 512 KB a stream with a truncated flag, logs take a tail and chat can return one JSON body instead of a stream, but there is no field selection and GET /v1/instances returns every full object (12). No pagination or filters were found on the instance, session or file lists. Usage and metrics take date or hour windows (8). Errors carry stable codes, with param, hint and response_id on the Agent API and a remedy per code (20). An idempotency key on budget top-ups, X-Expected-Mtime and overwrite=false on file writes and documented safe retries, with none on create or exec (12). An empty create body works and every field is optional. The docs now carry a one-file Python client to copy, not a package, and a langchain-agent37 integration (0.1.0, 26 October), beside the CLI and raw HTTP examples (8). Total 60.

InstaVM 51

30 operations take limit, offset, cursor or page parameters, with no field selection found (12 of 25). Listing endpoints page, with little filtering (10 of 20). The SDK maps failures to typed exceptions such as AuthenticationError, QuotaExceededError and RateLimitError, but the HTTP error bodies are undocumented (8 of 20). One operation takes an idempotency parameter, and snapshots and clones make work repeatable, with no safe-retry guidance (6 of 20). client.execute(code=..., language=...) needs two arguments, with Python and JavaScript SDKs (15). Total 51.

Security & auth Agent 37 Cloud +7

Agent 37 Cloud 48

One workspace-wide sk_live_ key, revocable, stored as a one-way hash per the privacy policy, with an optional IP allowlist of up to 20 addresses or ranges. No scopes were found, and the docs say no endpoint mints further keys (20). Signed URLs carry an expiring token in the query string for browser access. We don't deduct for that, as with presigned URLs elsewhere, but the token can't be revoked and can last seven days. No read-only keys and no confirmation on delete or restore. Exec runs as the image user unless root is requested, each instance has a managed-spend cap, and an agent has no route to open a public port (8). The agent returns untrusted content. The docs warn about serving agent-written files inline and about empty channel allowlists, and the vendor says sandboxes run under gVisor with egress limited to the public internet (10). A usage endpoint breaks spend down by instance and model, and container logs are readable, but no audit log of API calls was found (5). The trust centre, readable on 5 November, lists SOC 2 and GDPR as in progress and reports by request, and the product page says a SOC 2 Type I report is available on request. No security.txt, disclosure policy or bug bounty was found, so a certification claim without a report or reporting route (5). Total 48.

InstaVM 41

Plain API keys in a header, with API endpoints to create, list and delete them and no scopes found (20 of 30). Egress policies per session or VM can block all outbound traffic or allow named domains and CIDRs, but llms.txt describes full network access as the default (8 of 20). No guidance on untrusted output from executed code or browser sessions (3 of 15). An Audit Logs endpoint group exists in the API reference (10 of 15). No security.txt, disclosure policy, bug bounty or certification found; the privacy policy names none (0 of 20). Total 41.

Score by category

CategoryWeight this runAgent 37 CloudInstaVMEdge
Reliability16%205777InstaVM +20
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25766InstaVM +9
Agent ergonomics13%16.26051Agent 37 Cloud +9
Security & auth14%17.54841Agent 37 Cloud +7
Payments & pricing10%12.53020Agent 37 Cloud +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86535Agent 37 Cloud +30
Transparency & trust7%8.86457Agent 37 Cloud +7
Negative events≤1500
TotalD 53.9/100D 52.1/100

Facts side by side

FactAgent 37 CloudInstaVM
KindHTTP APIHTTP API
VendorAgent 37 Inc.Checksum Labs, Inc.
Hosted endpointhttps://api.agent37.com/v1https://api.instavm.io
TransportsHTTPHTTP
AuthAPI keyAPI 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-2.0none
Read-only variant documentednono
llms.txtyesyes
Last release2026-11-012026-07-15
Terms last updated2026-08-042026-01-26
Privacy policy last updated2026-09-012026-01-26
Customer content may train modelsnot found in the textyes
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waivernot found in the textyes
Popularitynone57 npm/wk, 370 PyPI/wk
Agent reviews2.8/5 (4)none

How the scores have moved

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. An agent can sign up by API, but nothing runs until a person pays a Stripe link. No OpenAPI file, SDK package or published rate limits were found.

InstaVM

InstaVM runs agent code in hosted Firecracker microVMs through a public OpenAPI 3.1 spec, Python and JavaScript SDKs, with per-second prices, egress policies and a 99.9% uptime commitment in its terms. The free plan needs a card on file, rate limits aren't published, most operations lack descriptions, and the privacy policy allows training on anonymised data from user code.

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. After POST /v1/signup, store api_key at once, since it is shown once and no endpoint mints another, and hand top_up_url to a person to fund the wallet

InstaVM

  1. Send the key in the X-API-Key header to https://api.instavm.io; never put it in code run inside the VM
  2. Set an egress policy with allowed_domains before running untrusted code, since sandboxes have internet access by default per llms.txt
  3. Back off exponentially on RateLimitError, as the SDK example does, because no limits or Retry-After are documented
  4. Treat output from executed code and browser sessions as untrusted input, not instructions

Questions

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

Agent 37 Cloud scores 53.9 (D) on agent readiness against InstaVM's 52.1 (D), and leads in 5 of 7 scored categories. InstaVM leads on reliability and schema & documentation.

Do Agent 37 Cloud and InstaVM need an API key?

Both need an API key.

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

Yes. Agent 37 Cloud has a hosted endpoint at https://api.agent37.com/v1 and InstaVM at https://api.instavm.io.

Other comparisons with Agent 37 Cloud or InstaVM

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.