Use the loopback-connector module to build a LoopBack connector to back-end data sources
such as databases or web services.  There are many existing connectors for the most popular data sources; see:
- [Database connectors](http://loopback.io/doc/en/lb3/Database-connectors.html) (for example, MongoDB, MySQL, Oracle).
- [Other connectors](http://loopback.io/doc/en/lb3/Other-connectors.html) (for example, REST, SOAP).

To build a new data source connector that doesn't yet exist, see [Building a connector](https://loopback.io/doc/en/lb3/Building-a-connector.html).
