App Components are a new platform feature for developers to build apps directly in the Asana UI. Building and testing App Components is now easier with the launch of our new, interactive UI Builder.
Use the UI Builder to:
- Test each of the different component types like Lookups (with Typeahead), Modal Forms, Widgets, and Rule Actions.
- Edit the template responses and watch the App Component dynamically change.
- Try out your own responses for accuracy and see detailed error messages.
Try it out today. We can’t wait to see what you create! 
Thanks for building with Asana,
Katy, API Product Manager