> ## Documentation Index
> Fetch the complete documentation index at: https://docs.burn0.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# burn0 dev

> Run your app with burn0 cost tracking

# burn0 dev

Runs your app with burn0 preloaded — no code changes needed.

```bash theme={null}
npx burn0 dev -- node app.js
npx burn0 dev -- npm start
npx burn0 dev -- next dev
```

## How it works

`burn0 dev` uses Node.js `--require` to preload burn0 before your app starts. This means:

* No `import '@burn0/burn0'` needed in your code
* Works with any Node.js app
* Cost tracking is active for the entire process

## Examples

```bash theme={null}
# Run a Node.js script
npx burn0 dev -- node server.js

# Run an npm script
npx burn0 dev -- npm run start

# Run Next.js dev server
npx burn0 dev -- npx next dev

# Run with tsx
npx burn0 dev -- npx tsx src/index.ts
```

## When to use `burn0 dev` vs `import`

| Approach                | Best for                       |
| ----------------------- | ------------------------------ |
| `import '@burn0/burn0'` | Production, permanent tracking |
| `burn0 dev -- ...`      | Quick testing, no code changes |

<Tip>
  Use `burn0 dev` when you want to try burn0 on an existing project without modifying any files. Use the `import` approach when you want permanent cost tracking.
</Tip>