# Data Exchange via Workist API

Workist provides a REST API for data exchange. Through the API you:

- upload documents to a channel,
- retrieve processed documents and report the result of the import into your system,
- set sender and subject, assign documents to users or delete them,
- transfer master data.

The API works on a pull basis: your system asks Workist for new results. If Workist should notify your system about events, also set up [webhooks](/en/docs/data-exchange/webhooks.md).

For more information on using the API, see the [API Documentation](/en/docs/api-documentation.md).

## Retrieving Lookup IDs for the API {#lookup-ids}

Every master data import belongs to a lookup definition. Users with the Manager, IT or Admin role create lookup definitions themselves in the [Master Data Hub](/en/docs/master-data/master-data-hub.md) (see [Users and roles](/en/docs/administration/users-and-roles.md)).

You find the ID of a lookup definition in two places.

**In the Master Data Hub:** The overview lists all lookup definitions with their ID. The ID is also shown on the detail page of the lookup definition.

**In the channel:**

1. Open the Workist interface: [https://wb.workist.com/](https://wb.workist.com/)
2. Select a channel, open the three-dot menu in the top right, and click "Manage channel".
3. Select "Master Data" from the list.
4. The ID of each selected lookup definition is shown below it. Clicking the ID copies it to the clipboard.