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

# List Folders

Lists the folders templates are filed into, with each folder's mode and how many templates it holds.

This is the only endpoint that returns folder IDs. Without it, `folder_id` on [Create Template](/api-reference/templates/create-template) can only be omitted — letting the API pick a folder — or guessed from an integer read out of an app URL.

## Modes

Folders are mode-scoped, matching the [transactional / marketing split](/learn/templates/projects#transactional-vs-marketing-templates). Filter with `purpose` to get just one side:

```bash theme={null}
curl "https://app.lettr.com/api/folders?purpose=campaign" \
  -H "Authorization: Bearer $LETTR_API_KEY"
```

A template's `folder_id` must name a folder of the same mode as its `purpose`.

<Note>
  A folder's mode does not set its templates'. Filing a template in a marketing folder does **not** make it a marketing template — only `purpose` on the template does.
</Note>

## Read-only

Folders are created and managed in the app. There is no API to create, rename or delete one, because deleting a folder moves or deletes the templates inside it.