---
name: sandbox-migrate-to-next
description: Migrate Cloudflare Sandbox apps from stable @cloudflare/sandbox to @cloudflare/sandbox@next (SDK 1.0 preview). Use sandbox-next for apps already on the preview.
---
# Migrate stable → Sandbox SDK 1.0 preview (`@next`)
**Perform** the port. Follow the steps in order. Depth lives in docs—fetch the linked page when a step needs detail.
Human guide: [Migrate](https://developers.cloudflare.com/sandbox/sdk/migrate/index.md) · [1.0 preview](https://developers.cloudflare.com/sandbox/index.md)
**New projects** should start on `@next` (**`sandbox-next`**), not this skill. **Day-to-day stable work** → **`sandbox-stable`**. Deprecated-API cleanup **without** moving to `@next` → [2026 deprecation guide](https://developers.cloudflare.com/sandbox/sdk/migrate/index.md) first if needed.
Existing apps should migrate **when you can**, so you are ready when 1.0 becomes the stable release. Do **not** force production cutover without the user agreeing.
**Prefer installed `@next` types and the migrate doc over memory.**
## Workflow
1. **Review** hard rules and the replacement map
2. **Audit** the codebase; list hits and target shapes
3. **Clarify** with the user (cutover, bridge, Python image, unclear sites)
4. **Upgrade** package, image, and code
5. **Validate**
Stop after any step that needs a user decision.
## Hard rules
- Worker package and container image must be the **same** `@next` line.
- Production cutover uses **immediate** container rollout. Stable and `@next` control protocols are incompatible both ways; gradual rollout leaves a broken mixed window. In-flight container work can stop.
- After cutover, `await sandbox.exec(...)` means process **started**, not command **finished**.
- Argv is as-is (no implicit shell). Shell syntax needs an explicit shell binary.
- Process handles have **no stdin** → terminals for interactive input.
- Observation `timeout` / `AbortSignal` cancel the **wait only**, not the process.
- No single retry loop for every error.
- Do not invent APIs (`gitCheckout` on core, process stdin, string-exec completion helper).
- Self-deployed bridge stays on **stable** (not part of the preview line yet).
## Replacement map
| Stable | `@next` |
| ------ | ------- |
| `SANDBOX_TRANSPORT` / `transport` / `setTransport` | Remove — RPC only |
| `await sandbox.exec("cmd")` → buffered result | `await sandbox.exec(argv)` → handle, then `output` / waits |
| `execStream` / `startProcess` | Same handle: `logs`, `waitFor*`, `kill` |
| Default / named sessions | Gone — `cwd`/`env` per launch, or one shell script |
| `sandbox.terminal(request)` / session terminal | `createTerminal` + `terminal.connect(request)` |
| xterm `sessionId` | `terminalId` |
| Interpreter methods on `Sandbox` | `withInterpreter` → `sandbox.interpreter.*` |
| `gitCheckout` | argv `git` via `exec` |
| String kill signals | Numeric only |
| Files, mounts, backups, ports, tunnels, `proxyToSandbox` | Mostly unchanged (ignore session/transport bits on stable pages) |
Depth: [Migrate](https://developers.cloudflare.com/sandbox/sdk/migrate/index.md) · after port, day-to-day → **`sandbox-next`**
## Audit
```sh
rg 'SANDBOX_TRANSPORT|transport:|setTransport|enableDefaultSession|createSession|getSession|deleteSession|execStream\(|startProcess\(|killProcess\(|sandbox\.terminal\(|sessionId|gitCheckout\(|SandboxTransport|ExecutionSession'
```
Also: string `exec(`, `cd` then a later `exec`, bare `createCodeContext` / `runCode` on `Sandbox`.
## Clarify (ask when needed)
- OK to cut production with `--containers-rollout=immediate` (live processes/terminals/streams may stop)?
- Self-deployed bridge? Leave on stable.
- Python interpreter → **`-python`** image variant?
- Call sites not covered by the map?
## Upgrade
### Package and image
```sh
npm install @cloudflare/sandbox@next
```
```dockerfile
FROM cloudflare/sandbox:next
# Python: cloudflare/sandbox:next-python
```
Same prerelease tag on Worker and image when not on floating `next`.
### Code by area
Apply replacements from the map. For each area, implement from the doc—not from stable habits:
| Area | Doc |
| ---- | --- |
| Commands / handles / waits | [Processes](https://developers.cloudflare.com/sandbox/index.md) · [Processes API](https://developers.cloudflare.com/sandbox/index.md) |
| `cwd` / `env` / secrets | [Environment](https://developers.cloudflare.com/sandbox/index.md) · [Outbound traffic](https://developers.cloudflare.com/sandbox/sdk/guides/outbound-traffic/index.md) |
| Drop sessions | [Migrate](https://developers.cloudflare.com/sandbox/sdk/migrate/index.md) · [Lifecycle](https://developers.cloudflare.com/sandbox/index.md) |
| Terminals | [Terminals](https://developers.cloudflare.com/sandbox/index.md) |
| Interpreter | [Interpreter](https://developers.cloudflare.com/sandbox/index.md) |
| Errors | [Errors](https://developers.cloudflare.com/sandbox/index.md) |
| Durable job across requests | [Process execution — lifetime / durability](https://developers.cloudflare.com/sandbox/index.md) |
**Commands (shape):**
```ts
// Before (stable)
const result = await sandbox.exec("npm test");
// After (@next)
const process = await sandbox.exec(["/bin/bash", "-lc", "npm test"]);
const result = await process.output({ encoding: "utf8" });
```
```ts
const server = await sandbox.exec(["/bin/bash", "-lc", "npm run dev"], {
cwd: "/workspace/app",
});
await server.waitForPort(3000, { timeout: 60_000 });
await server.kill(); // numeric; default 15
```
**Terminals (shape):**
```ts
const terminal = await sandbox.createTerminal({ command: ["bash"], cwd: "/workspace" });
const t = await sandbox.getTerminal(terminal.id);
if (!t) return new Response("terminal gone", { status: 410 });
return t.connect(request, { cursor, cols, rows });
```
**Interpreter (shape):**
```ts
import { Sandbox as BaseSandbox } from "@cloudflare/sandbox";
import { withInterpreter } from "@cloudflare/sandbox/interpreter";
export class Sandbox extends BaseSandbox<Env> {
interpreter = withInterpreter(this);
}
```
**Git (shape):**
```ts
const clone = await sandbox.exec(
["git", "clone", "--depth", "1", "--", repoUrl, "/workspace/repo"],
{ cwd: "/workspace" },
);
const result = await clone.output({ encoding: "utf8" });
```
Delete transport settings entirely. Remove session APIs. Isolate users with **separate sandbox IDs**.
### Deploy cutover
Staging/branch first. Production is **one** deploy of matching Worker + image:
```sh
npx wrangler deploy --containers-rollout=immediate
```
Leave `rollout_active_grace_period` at default `0` (or set `0` if raised). After cutover, pre-deploy process/terminal IDs are invalid. Details: [Migrate](https://developers.cloudflare.com/sandbox/sdk/migrate/index.md) · [Container rollouts](https://developers.cloudflare.com/containers/configuration/rollouts/index.md)
## Validate
1. Lockfile + Dockerfile on the same `@next` line
2. Typecheck against `@next`
3. Smoke argv `exec` + `output({ encoding: "utf8" })`
4. Smoke long process / terminal / interpreter if used
5. Errors distinguished: unavailable / interrupted-RPC / stale / local wait
6. No live secrets in sandbox env
7. Grep again for removed APIs
8. Production used `--containers-rollout=immediate`
Then day-to-day work uses **`sandbox-next`**.
## Red flags — stop and fix
- Mixing `@next` Worker with stable image (or reverse)
- Gradual container rollout for this cutover
- Treating `await exec` as command completion
- Assuming `cd` / exports persist across `exec` calls
- One retry wrapper for every error
- Inventing `gitCheckout`, process stdin, or undocumented APIs
- Keeping pre-cutover process/terminal IDs after deploy
- Forcing production cutover without user agreement
- Putting live secrets in `setEnvVars` / launch `env`