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crackd

Unbreakable boxes for code you didn't write

Cheap. Reliable. Open in 64 ms.

50 free box hours every month. No card required.

Drawing of a server region as a grid of boxes, one box per customer sandbox.Your boxOther customers' boxes18Free slot
No box open

# pick a script below to open a box

Built so a bad run stays a bad run

Sooner or later your agent writes code that loops forever, deletes files or tries to phone home. None of it gets past the box.

microVMguest kernelyour code

A kernel of its own

Every box is a Firecracker microVM, not a container sharing the host's kernel.

pypi.org169.254.169.254evil.example

No network until you say so

Outbound traffic stays blocked until you allow a domain.

step 14try atry b ✓try c

Fork a box mid-task

Copy a running box in 40 ms and keep whichever try worked.

Fast enough to open one per tool call

Boxes resume from a memory snapshot instead of booting, so there's no reason to keep one warm or share it between users.

Pay per second

$0.10per hour while running

An agent running 2,000 one-minute tasks a day pays about $96 a month.

vCPU
2
RAM
4 GB
Disk
20 GB
  • 50 free box hours every month
  • Billed per second, nothing when idle
  • Snapshots, forks and preview URLs
  • Up to 100 boxes at once
Running more than 10,000 hours a month? Talk to us

Time to first output

  • crackd box64 ms
  • Container cold start900 ms
  • Fresh cloud VM4.5 s
  • Kubernetes pod7.0 s

Median of 1,000 runs of python -c "print(1)", from API call to first byte of output.

The whole API

import { Crackd } from "@crackd/sdk"const crackd = new Crackd()// Open a box from any OCI imageconst box = await crackd.sandboxes.create({ image: "python:3.13" })// Run whatever the model wroteconst run = await box.exec("python agent_step.py")console.log(run.stdout, run.exitCode)// Throw it awayawait box.destroy()
box.create(image)
Open a box from any OCI image
box.exec(cmd)
Run a command, stream stdout and stderr
box.files.write(path, data)
Put files in before you run
box.expose(3000)
Get a public HTTPS URL for a port
box.snapshot()
Freeze memory and disk to resume later
box.fork(3)
Start copies from the current state
box.destroy()
Wipe memory and disk, stop billing

Questions teams ask first

FAQ

Containers share the host kernel, so one kernel exploit reaches every container on the machine. Each crackd box is a Firecracker microVM with its own guest kernel, the same isolation AWS Lambda uses.

Something else? Email the founders

Open your first box

Create a key, install the SDK, and your agent has somewhere safe to run code before your coffee is done.

Read the API