JS Report is very cool tool for generating pdf, excel, docx, html, csv using HTML and JavaScript. It provide lots of feature to customize the html and JS code. You can also add charts in PDF as well.

It also provide an online editor where you can create html to generate PDFs.

In My Implementation You have to create template and pass template name and JSON data in the server action and you can download PDFs in the OutSystems.

So next time you what to change any layout things you can do with out changing any code in OutSystems.

You can create cloud account to test it.

1. Go to https://jsreportonline.net/sign and create your account 

Or you can play with lots of samples available here https://playground.jsreport.net/