kosa8 vs Modal Sandboxes

01The 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].

02Modal 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.

03Where 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].

04Where 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].

05Moving 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].

06Questions

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