Modal Sandbox alternatives in 2026

01Why teams look for Modal alternatives

• No self-hosting. Modal's docs do not describe a self-hosted or air-gapped option.
• Snapshots end the sandbox. Taking a memory snapshot terminates it, and memory snapshots are alpha with a 7-day expiry [5].
• Enterprise-only controls. Audit logs and SAML SSO are on Enterprise [2] [7].
• gVisor by default. A default sandbox runs on a user-space kernel, not its own VM [1].

02Modal alternatives at a glance

Listed in no order of merit. Each line sums up the comparison page it links to, where every fact cites that vendor's own pages.

03The short verdict

Choose Modal if

• your sandboxes need GPUs: Modal bills them per second from T4 to B300 [2];
• you want Modal's regions, down to country level, without running hosts [4];
• you already run inference or batch jobs on Modal and want sandboxes beside them, from Python, JavaScript or Go [1];
• you need a published SOC 2 Type II report today [3].

Choose kosa8 if

• code may not leave your machine, your servers or an air-gapped site;
• you want to fork a running sandbox into live copies, memory and processes included, without stopping it [10];
• you want to rewind a whole machine after an agent breaks it [11];
• you want API keys added outside the VM by an egress broker, and an audit log anyone can verify [8].

04Modal and kosa8, feature by feature

Bracketed numbers point to the sources. "Not documented" means the vendor's own pages did not say on 2026-11-14; it does not mean the feature is missing.

05Where Modal is stronger

• GPUs. Modal sandboxes can have GPUs; kosa8 sandboxes have none today [1] [16].
• Regions and managed scale. Many regions, chosen per sandbox, with no hosts to run [4]. kosa8 Cloud has two regions [10].
• Compliance paperwork. Modal points to a SOC 2 Type II report and offers HIPAA on Enterprise [3]; kosa8 has no SOC 2 report yet [17].
• A wider platform. Sandboxes sit next to Modal's functions, inference and batch jobs, and its egress controls take both CIDRs and domains [6].

06Where kosa8 is different

• Runs where you need it. The same sandbox runs on a Mac, a Linux box, Windows through WSL2, your own servers or air-gapped [9].
• Live fork and rewind. kosa8 saves memory, processes and disk and forks a running sandbox without stopping it [10].
• Keys stay out. An egress broker on the host adds the real API key on the way out; the sandbox sees a placeholder [17].
• Verifiable audit on every plan. The hash-chained log is checked with one command, not an Enterprise add-on [15].

07Moving from Modal to kosa8

Modal's quickstart looks up an app, creates a sandbox, runs a command and terminates it [1]. kosa8 Cloud has the same shape; the main change is the client and that exec takes a list.

Modal, from its Sandboxes guide:

sb_app = modal.App.lookup("my-app", create_if_missing=True)
sb = modal.Sandbox.create(app=sb_app)

p = sb.exec("python", "-c", "print('hello')", timeout=3)
print(p.stdout.read())

sb.terminate()

The same on kosa8 Cloud (Python, pip install kosa8):

from kosa8 import Kosa8Cloud

cloud = Kosa8Cloud()  # reads KOSA8_API_KEY
box = cloud.sandboxes.create(template="python", sleep_after_s=600)
r = box.exec(["python3", "-c", "print('hello')"])
print(r.exit_code, r.stdout)
box.delete()

• Sandbox.create(app=...) becomes cloud.sandboxes.create(template=...); there is no app object.
• sb.terminate() becomes box.delete(), or box.sleep() to keep the disk for $0.08 per GB-month [11].
• Modal's block_network=True maps to --egress deny on a local sandbox; a CIDR or domain allow-list maps to --egress-allow [12]. kosa8 Cloud has no egress setting yet [13].
• GPU workloads have no kosa8 equivalent; keep those on Modal.
• Each kosa8 Cloud exec runs in a fresh container on the sandbox's disk: files under /workspace persist between commands, background processes do not. A buffered exec stops at 90 seconds; send stream: true for longer commands [10].
• Templates today are base (Alpine), python (Python 3.12) and node (Node.js 22) [10].
• An organization runs up to 20 sandboxes at once on kosa8 Cloud unless you ask for more [11].

08Questions

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