kosa8 vs Blaxel

01The short verdict

Choose Blaxel if

• you want sandboxes that sit on standby forever and resume in under 25 ms, billed only while active [2] [5];
• you want agent hosting, batch jobs and MCP hosting on the same platform [5];
• you need very high concurrency tiers, up to 100,000+ through sales [5];
• you need SOC 2 and HIPAA reports today [11].

Choose kosa8 if

• sandboxes must run on laptops, your servers or an air-gapped site with no outside control plane [14];
• you need fork and checkpoints as generally available features [15];
• you want an audit log of sandbox actions anyone can verify [20];
• you want a freeze for every sandbox and key in one call [18].

02Blaxel 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 Blaxel is stronger

• Standby and resume. Under 25 ms resume and no charge while on standby [2] [5].
• Managed scale. Concurrency tiers into the 100,000s [5]; kosa8 Cloud defaults to 20 [16].
• A wider agent platform. Agent hosting, batch jobs, MCP hosting and an egress proxy with secrets injection [5] [7].
• Compliance paperwork. SOC 2 and HIPAA reports on request [11]; kosa8 has no SOC 2 report yet [22].

04Where kosa8 is different

• Fully yours to run. Blaxel's own-hardware option keeps its control plane [5]; kosa8 runs offline [14].
• Generally available fork and rewind. Blaxel's fork and snapshots are in private preview [3]; kosa8's are standard [15].
• A documented audit log with hash chaining and SIEM streaming [18].
• More SDKs. kosa8 adds Ruby and Java [15].

05Moving from Blaxel to kosa8

Blaxel's docs create a sandbox, run a process and delete it [9] [12] [2].

Blaxel, from its docs:

import { SandboxInstance } from "@blaxel/core";
const sandbox = await SandboxInstance.createIfNotExists({
  name: "my-sandbox",
  image: "blaxel/base-image:latest",
  memory: 4096,
  region: "us-pdx-1"
});
const result = await sandbox.process.exec({
  command: "ls /",
  waitForCompletion: true
});
await SandboxInstance.delete("my-sandbox");

The same on kosa8 Cloud (TypeScript, npm install @kosa8/sdk):

import { Kosa8Cloud } from '@kosa8/sdk';

const cloud = new Kosa8Cloud(); // reads KOSA8_API_KEY
const box = await cloud.sandboxes.create({ template: 'python' });
const r = await box.exec(['python3', '-c', "print('hello')"]);
console.log(r.exitCode, r.stdout);
await box.delete();

• process.exec({ command }) becomes box.exec(['sh', '-c', command]); it waits for completion by default.
• Region names change: us-ash1 (Dallas) or eu-hel1 (Helsinki) [15].
• Blaxel's automatic standby maps to sleep_after_s; a sleeping kosa8 Cloud sandbox costs $0.08 per GB-month and wakes on the next command [16].
• allowedDomains maps to --egress-allow on a local sandbox [17].
• 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 [15].
• Templates today are base (Alpine), python (Python 3.12) and node (Node.js 22) [15].
• An organization runs up to 20 sandboxes at once on kosa8 Cloud unless you ask for more [16].

06Questions

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