---
url: /reference/InputOptions.devtools.md
---
# devtools

* **Type**: object with the properties below
* **Optional**
* **Experimental**

Devtools integration options.

When enabled, Rolldown writes JSON-lines devtools output under
`node_modules/.rolldown/{session_id}/`, resolved against [`cwd`](./InputOptions.cwd).
Consumers can parse the output with `@rolldown/debug` after
`await bundle.close()` resolves.

## sessionId?

* **Type**: `string`
* **Optional**