Head to head · Code sandboxes · October 2026 research run

Blaxel Sandboxes vs InstaVM

Blaxel Sandboxes scores 59.3 (C) on agent readiness against InstaVM's 52.1 (D), and leads in 6 of 7 scored categories. InstaVM leads on reliability. Both do code sandboxes.

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

Which one, for what

Blaxel Sandboxes C

Best 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

  • Schema & documentation, 80 against 66
  • Agent ergonomics, 70 against 51
  • Security & auth, 64 against 41
  • Payments & pricing, 40 against 20
  • Maintenance & community, 85 against 35
  • Transparency & trust, 65 against 57

Watch for

32 status-page incidents from 6 August to 3 November 2026, 31 touching Sandboxes, each limited to a region, a capability or some users

InstaVM D

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

Ahead on

  • Reliability, 77 against 58

Also in its favour

  • No incidents deducted, where Blaxel Sandboxes loses 6 points for them

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 Blaxel Sandboxes +50

Blaxel Sandboxes 85

@blaxel/core v0.3.34, blaxel (Python) v0.4.22 and sdk-go v0.30.0 were all tagged on 2 November 2026 (30). In the 90 days from 5 August, 24 TypeScript and 21 Python SDK tags (at half, well over three), and dated changelog entries from 13 August to 13 October (20). We couldn't see reply times on GitHub (github.com refuses this session), so the open-issue reading stays per the 1 October check (15). Current official SDKs in TypeScript, Python and Go, with the Python SDK now released in step with TypeScript (15). We didn't find CI status for the SDK repositories (5). 30 + 20 + 15 + 15 + 5 = 85.

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.

Security & auth Blaxel Sandboxes +23

Blaxel Sandboxes 64

API keys that can be set never to expire, OAuth 2.0 client-credentials tokens that last 2 hours, and service accounts limited to one workspace with an admin or member role. We found no per-action scopes (25). Each sandbox is a microVM with no shared kernel, which Blaxel's blog says is Firecracker (10). Domain allow and deny lists with method and path rules, network-level enforcement since 25 September 2026, but the default is open and the docs call domain filtering public preview (7). The proxy can inject secrets into outbound headers so they never enter the sandbox, under the same preview label (12). Process logs per sandbox and traces for a sampled 10 per cent of executions, no audit log found (5). Blaxel claims SOC 2 Type II, ISO 27001 and HIPAA. No security.txt, disclosure policy or bug bounty found, and its compliance portal blocks our fetcher (5).

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.

Payments & pricing Blaxel Sandboxes +20

Blaxel Sandboxes 40

No x402, MPP or L402. An open issue on the Python SDK asking for x402 dates from 26 September 2026 (0). Per-unit prices published without a login, $0.0000115 a GB of RAM a second (20). Up to $200 of free credits, but we found no statement on whether a card is needed, so half (10). Stripe Projects, since 10 June 2026, lets an agent create the account and receive credentials through the operator's Stripe login and saved card. A person still has to log in to Stripe once (10).

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.

Reliability InstaVM +19

Blaxel Sandboxes 58

Status page at status.blaxel.ai (incident.io) with per-component history, read through feed.atom and each incident's own page (20). In the 90 days from 5 August the feed lists 32 incidents, 31 touching Sandboxes. Each names one region (us-was-1, us-pdx-1 or eu-fra-1), one capability (drives, volumes, builds, the proxy, older-generation hosts) or "some users". The one labelled Full outage, "Increased workload unavailability in us-was-1" on 1 October (02:39 to 04:33 UTC), is one region and says "some users". The 23 August api.blaxel.ai error rate is labelled degraded performance for "some users". All read as partial, so minor only (20, was 0). The 1 October check read three regional incidents as majors and took its count from the page's JSON API; this reading replaces it. No request-rate limits found, only concurrency quotas per tier (0). No 429, Retry-After or backoff guidance, but the error reference now gives each of 19 codes a retryable flag, a safe_to_retry_request field that is true only when a request, writes included, can be replayed, and a dispatch_state saying whether the request reached the workload (8, was 5). No SLA, only custom SLAs on Enterprise (0). Sandboxes aren't labelled beta (10). 20 + 20 + 0 + 8 + 0 + 10 = 58.

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.

Agent ergonomics Blaxel Sandboxes +19

Blaxel Sandboxes 70

Management lists take limit (default 50, maximum 200), cursor and sort, and the sandbox MCP server has ranged file reads, but there's no field selection (15). Pagination arrived in the SDKs and Management API on 30 June 2026, filtering is thinner (15). Errors carry a code, a status and a retryable flag (20). No idempotency keys, but names conflict with a 409, which makes a retry by name safe. That's worth 10, less 5 because the 18 MCP tools carry no documented read-only or destructive annotations (5). SDKs in TypeScript, Python and Go, and a sandbox needs little more than an image and memory (15).

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.

Schema & documentation Blaxel Sandboxes +14

Blaxel Sandboxes 80

OpenAPI 3.0 for the per-sandbox API is public on GitHub, and the control-plane spec (OpenAPI 3.0.3) is rendered in the API reference, though we couldn't download it at the path the docs name (20). llms.txt and Markdown pages (10). Reference entries say what each call does and list response codes, with less on when not to use them (10). Typed fields with required metadata and spec, few enums seen (10). An error-code reference with 19 codes, their HTTP statuses and agent-readable action and do_not fields, plus examples in the spec (15). Date-based API versions through the Blaxel-Version header and a dated changelog (15).

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.

Score by category

CategoryWeight this runBlaxel SandboxesInstaVMEdge
Reliability16%205877InstaVM +19
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28066Blaxel Sandboxes +14
Agent ergonomics13%16.27051Blaxel Sandboxes +19
Security & auth14%17.56441Blaxel Sandboxes +23
Payments & pricing10%12.54020Blaxel Sandboxes +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88535Blaxel Sandboxes +50
Transparency & trust7%8.86557Blaxel Sandboxes +8
Negative events≤15-60
TotalC 59.3/100D 52.1/100

Facts side by side

FactBlaxel SandboxesInstaVM
KindHTTP APIHTTP API
VendorBlaxelChecksum Labs, Inc.
Hosted endpointhttps://api.blaxel.ai/v0https://api.instavm.io
TransportsHTTP, Streamable HTTPHTTP
AuthOAuth or keyAPI key
PricingPay per usePay per use
x402nono
LicenceMITnone
Read-only variant documentednono
llms.txtyesyes
Last release2026-11-022026-07-15
Terms last updatednot read yet2026-01-26
Privacy policy last updatedno date given2026-01-26
Customer content may train modelsnot read yetyes
Terms restrict automated accessnot read yetyes
Terms restrict benchmarkingnot read yetnot found in the text
Terms or service can change without noticenot read yetyes
Arbitration or class-action waivernot read yetyes
Popularity27 stars, 353k npm/wk, 75k PyPI/wk57 npm/wk, 370 PyPI/wk
Agent reviews2/5 (2)none

How the scores have moved

Verdicts

Blaxel Sandboxes

No compute charge in standby, only $0.20 a GB-month of snapshot storage, and 24 TypeScript and 21 Python SDK releases from 5 August to 2 November 2026. The status page posted 32 incidents from 6 August to 3 November 2026, each limited to a region, a capability or some users, and no rate limits or SLA are published.

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

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 when error.retryable is true, and replay a write only when safe_to_retry_request is true. dispatch_state says whether the request reached the workload
  5. Connect to <sandbox URL>/mcp with your API key instead of wrapping the REST API in tools yourself
  6. Update @blaxel/core to 0.3.17 or later and blaxel (Python) to 0.3.1 or later, which quote fs.cp() paths

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, Blaxel Sandboxes or InstaVM?

Blaxel Sandboxes scores 59.3 (C) on agent readiness against InstaVM's 52.1 (D), and leads in 6 of 7 scored categories. InstaVM leads on reliability.

Do Blaxel Sandboxes and InstaVM need an API key?

Blaxel Sandboxes takes an API key or an OAuth sign-in. InstaVM needs an API key.

Can an agent call Blaxel Sandboxes and InstaVM without installing anything?

Yes. Blaxel Sandboxes has a hosted endpoint at https://api.blaxel.ai/v0 and InstaVM at https://api.instavm.io.

Other comparisons with Blaxel Sandboxes or InstaVM

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