Links with URL's that are calculated at runtime are great to create lists of favorite links.
Here's how to do it:
1 - Create an External Site in the Web Flow
2 - Connect a Web Screen to this External Site
3 - Edit the Web Screen and add a Link widget
4 - Select the External Site in the Link Destination property
5 - Use Expression Editor to fill the URL parameter
For more information see:
"Add Dynamic URL" in OutSystems Service Studio Help
Right-click in the External Site element in the Flow canvas or in the eSpace tree.
Select the Add Dynamic URL operation.
A special screen input parameter is created: the name of this parameter is URL. This input parameter is special in the sense that you must not change its name.