YOUR FEEDBACK MATTERS
If you are an active Universal subscriber (or planning to become one), and are interested in additional Web API Service endpoints:
 - check the state of input data with 10+ of built-in and unlimited custom validation rules;
 - download PDF, RTF, etc. from Office documents or Mail Merge templates (RichTextMailMergeData) based on filtered data in databases; 
 - download PDF, RTF, etc. from Dashboard templates (DashboardData) based on filtered data in databases;
 - etc.

Please share your specific project requirements with us OR tell us how our Web API Service works for you:
https://www.devexpress.com/go/XAF_WebAPI_Feedback.aspx - THANKS!
We want to validate a few hypotheses using your feedback and also share our implementation considerations with you (to finalize this for production).

Relevant Documentation

Validation Module
https://docs.devexpress.com/eXpressAppFramework/113684/

Office Module
https://docs.devexpress.com/eXpressAppFramework/400003/

Dashboards Module
https://docs.devexpress.com/eXpressAppFramework/117449/xtensions