# Keep Alive

When `keepAlive` is enabled, the box stays on between sessions instead of auto-pausing when idle. Use it when you need a box to remain continuously available, for example to host a server, keep a long-running agent ready, or preserve an always-on development environment.

For most workloads, the default Box lifecycle is still the better choice. Boxes auto-pause when idle and are more cost-efficient for bursty workloads unless `keepAlive` is enabled.

---

## Create a keep-alive box

Use `keepAlive: true` when creating the box:

<CodeGroup>
```typescript box.ts
import { Box } from "@upstash/box"

const box = await Box.create({
  runtime: "node",
  size: "medium",
  keepAlive: true,
})
```

```python box.py
from upstash_box import Box

box = Box.create(
    runtime="node",
    size="medium",
    keep_alive=True,
)
```
</CodeGroup>

You can combine keep-alive with all normal Box features, including agent, git, shell, filesystem, public URLs, and snapshots.

---

## Sizes and specs

Boxes with `keepAlive` enabled use the same Box sizes as any other box. Pick the size with the `size` option when creating the box or in the Console during box creation.

| Size | CPU | Memory | Storage |
| --- | --- | --- | --- |
| `small` | 2 vCPU | 4 GB | 5 GB |
| `medium` | 4 vCPU | 8 GB | 10 GB |
| `large` | 8 vCPU | 16 GB | 20 GB |

The selected size determines the box's available CPU, RAM, and workspace storage whether `keepAlive` is enabled or not.

---

## Lifecycle differences

| | Default behavior | With `keepAlive: true` |
| --- | --- | --- |
| **Idle behavior** | Auto-pauses when idle | Stays on |
| **Pause / resume** | Supported | Not supported |
| **Best for** | Bursty workloads, task runners, on-demand agents | Always-on servers, long-running agents, warm environments |
| **Billing model** | Active usage based | Open-time / always-on based |

If you do not need the box to remain continuously available, keep `keepAlive` disabled.

---

## Init command

Boxes with `keepAlive` enabled can run a startup command whenever the box starts.

<CodeGroup>
```typescript box.ts
const box = await Box.create({
  runtime: "node",
  keepAlive: true,
  initCommand: "npm install && npm run dev",
})
```

```python box.py
box = Box.create(
    runtime="node",
    keep_alive=True,
    init_command="npm install && npm run dev",
)
```
</CodeGroup>

This is useful for:

- starting a web server
- launching a background process
- preparing a long-running agent environment
- restoring a development workflow automatically after the box starts

You can also manage the init command after creation:

<CodeGroup>
```typescript box.ts
await box.setInitCommand("npm run dev")

const command = await box.getInitCommand()
await box.deleteInitCommand()

console.log(box.keepAlive) // true
```

```python box.py
box.set_init_command("npm run dev")

command = box.get_init_command()
box.delete_init_command()

print(box.keep_alive)  # True
```
</CodeGroup>

Init command management is only available when `keepAlive` is enabled.

---

## Console

In the Upstash Console you can:

- enable **Keep alive** while creating a box
- choose the box **Size**
- manage the **Init Command** later from the box settings page

---

## When to use keep alive

Use keep-alive when the box itself needs to stay available between requests:

- hosting a dev server or app with a public URL
- keeping an agent warm for low-latency use
- preserving a long-running environment with startup automation

Avoid keep-alive when you only need a reusable workspace. In those cases, the default box lifecycle plus [Snapshots](/box/overall/snapshots) is usually enough.