# Directory: data-sources

The **mandatory** directory `data-sources` contains data-source definitions. A data-source-definition contains references to one or many data-sources, which you would like to load data from and convert to output using a transformer.

See: [Data-Source](https://onestopconcept.gitbook.io/open-endpoints/data-source-transformation#data-source).

![directory data sources](https://cdn.openendpoints.io/images/gitbook/directory-data-sources.png)