Sandbox Next by @cloudflare · Skillet

Sandbox Next

Build or maintain Cloudflare Sandbox apps on @cloudflare/sandbox@next (SDK 1.0 preview). Use sandbox-migrate-to-next when porting a stable app.

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SKILL.md

sandbox-next

Build or maintain Cloudflare Sandbox apps on @cloudflare/sandbox@next (SDK 1.0 preview). Use sandbox-migrate-to-next when porting a stable app.

Sandbox SDK — `@next` (1.0 preview)

Isolated Linux environments on Cloudflare Containers, driven from Workers.

Prefer preview docs and installed @next types over memory. APIs change; this skill is a gate, a contract, and a retrieval map—not a full manual.

We recommend new projects on this line. Apps still on the default package use sandbox-stable. Port only when asked, via sandbox-migrate-to-next.

1. Gate — confirm the package line

Before writing code, inspect the app:

3 files · 9 KB7 KB

Version history

If you find…	Action
Default `@cloudflare/sandbox` (no `@next`)	Stop. Load `sandbox-stable`. Do not apply this skill’s APIs.
User wants to port stable → `@next`	Stop. Load `sandbox-migrate-to-next`.
Self-deployed bridge only	Bridge is not on the 1.0 preview line yet. Keep bridge on stable package + image. Bridge (stable)

import { getSandbox, proxyToSandbox, Sandbox } from "@cloudflare/sandbox";

export { Sandbox };

const sandbox = getSandbox(env.Sandbox, "user-123");
const process = await sandbox.exec(["python3", "-c", "print(2 + 2)"]);
const result = await process.output({ encoding: "utf8" });
// result.stdout, result.exitCode

You need to…	Open
Orient / choose preview	1.0 preview overview
First Worker, wrangler, Dockerfile	Get started
`exec`, handles, readiness, durability	Process execution
Process API signatures	Processes API
Sandbox ID vs container vs sleep/destroy	Lifecycle
`cwd` / `env` / `setEnvVars`	Environment
Interactive PTY / browser terminal	Terminals · Terminals API
Python/JS code interpreter	Interpreter · Interpreter API
Extensions model	Extensions
Error classes and recovery	Errors · Errors API
Common failures	Troubleshooting
API hub	API reference
Files, mounts, backups, ports, tunnels, `proxyToSandbox`	Main docs for shared surfaces (ignore stable-only session/transport/`sandbox.terminal`): Files · Storage / mounts · Ports · Tunnels · Backups · Outbound traffic · Expose services · Production
Example apps	examples on `next`
Still on stable package	`sandbox-stable` · Main Sandbox docs
Porting an existing stable app	`sandbox-migrate-to-next` · Migrate

npm dependency	`@cloudflare/sandbox@next` (or another preview tag)
Container image	Same line (e.g. `cloudflare/sandbox:next`, `next-python`)

Sandbox Next

Sandbox SDK — `@next` (1.0 preview)

1. Gate — confirm the package line

2. Contract — non-negotiables

3. Retrieve — open the doc for the task

4. Before you ship

Sandbox SDK — @next (1.0 preview)

1. Gate — confirm the package line

2. Contract — non-negotiables

3. Retrieve — open the doc for the task

4. Before you ship

Sandbox SDK — `@next` (1.0 preview)