Localytics in-app messages can be generated without writing code using our creative builder, or you can upload custom HTML/CSS/Javascript which will be rendered as a webview. You may want to include a call to action (also known as a "CTA") within the creative that, when clicked, links the user to a location outside of the app, like a website or another page within your app.
If you are uploading a custom creative, you will need to append two parameters to the end of your URL/URI to tell the Localytics SDK to open the link outside the in-app message and to tag the impression. The parameters that should be appended are ampExternalOpen and ampAction as a query parameter.
Here is an example of a properly-constructed link that, if clicked within an in-app message, would send the URL-clicking user to the Localytics Docs site: http://docs.localytics.com/?ampExternalOpen=true&Action=click
To make the CTA within the app, replace http://docs.localytics.com/ with a URI your app recognizes and append with ampExternalOpen and ampAction