Sandbox Migrate To Next

# 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) con