Heterogeneous content in email inbox

Aspects of the present disclosure relate to systems and methods for integrating first class objects with email messages in an email inbox of an email client. In one example, a request is sent via the email client for first class object data to one or more data sources, where each data source of the one or more data sources includes first class object data of a different first class object type. The first class object data may be received at the email client from the one or more data sources. One or more first class objects may be created from the first class object data for injecting into an email inbox of the email client. The email inbox including at least some of the one or more first class objects and a plurality of email messages may be rendered in a user interface to the email client.