More and more individuals and organizations are making their data available online publicly, resulting in a growing market of technologies and services to help consume data and extract its real value. One of the several ways to publish data on the Web is via Web APIs. Unlike other approaches like RDF, Web APIs provide a simple way to query structured data by relying only on the HTTP protocol. Standards and frameworks such as Open API or API Blueprint offer a way to create Web APIs but OData stands out from the rest as it is specifically tailored to deal with data sources. However, creating an OData Web API is a hard and time-consuming task for data providers as they have to choose between relying on commercial solutions, which are heavy and require a deep knowledge of their corresponding platforms, or create a customized solution to share their data. We propose an approach that leverages on model-driven techniques to facilitate the development of OData Web APIs. The approach relies on a UML profile for OData allowing to annotate a UML class diagram with OData stereotypes. In this paper we describe the profile and show how class diagrams can be automatically annotated with such profile.