# Introduction

> Flax Cloud gives you instant, isolated cloud sandboxes you can drive from an API, SDKs, or a CLI. Run code, agents, builds, and live app previews in a disposable container.

**Flax Cloud** gives you instant, isolated Linux sandboxes in the cloud. Each one is a
disposable, hardened container you can create in seconds, drive over an API (or the Python and
JavaScript SDKs, or the `flax` CLI), and throw away when you're done.

Use them to run untrusted or AI-generated code, execute scripts and test suites, build steps,
power coding agents, control a real Chromium browser over CDP, or serve a live app preview you
can share with a link.

## Why Flax

- **Isolated by default.** Every sandbox runs with a hardened profile: dropped Linux
  capabilities, no privilege escalation, a process cap, and CPU/memory limits, on top of
  gVisor-hardened kernel isolation. See [Security](./security.md).
- **Fast to start.** Warm pools mean a sandbox is usually ready the moment you ask for one.
- **Drive it your way.** A clean REST API, first-class [Python](./sdk.md) and
  [JavaScript/TypeScript](./sdk-js.md) SDKs, and a [CLI](./sdk.md#cli).
- **Stateful when you want it.** Persist a workspace across stop/resume, capture reusable
  [snapshots](./concepts.md#snapshots), or [fork](./concepts.md#forks) a running sandbox.
- **Shareable previews.** Run a server and get a secret public URL with automatic TLS.

## Start here

- **[Quickstart](./quickstart.md)** - from zero to a running sandbox with a live preview.
- **[Core concepts](./concepts.md)** - sandboxes, templates, lifecycle, persistence, isolation.
- **[Python SDK & CLI](./sdk.md)** · **[JavaScript / TypeScript SDK](./sdk-js.md)**
- **[API reference](./api.md)** - every endpoint, request, and response.
- **[Troubleshooting](./troubleshooting.md)** - common errors and fixes.
- **[Launch readiness](./launch-readiness.md)** - what is enforced today and what still needs hardening.

## A first taste

```python
from flaxcloud import FlaxClient

flax = FlaxClient()  # reads FLAX_API_KEY

with flax.create_sandbox(template="python") as sb:
    result = sb.run("python3 -c 'print(2 ** 16)'")
    print(result.stdout)  # 65536
```

Bring your own agent framework, your own tooling, your own workflow. Flax is the compute
underneath.