Back story: One of my PHP web applications allows end-users to create reports. Whilst these are created in an HTML web-editor they're published to PDF.
All of the existing PHP libraries and API conversion services that I tried had some deal-breaking problem, so eventually I quit compromising and rolled my own service using the headless-Chrome-browser. Problem solved. Thank you Google!
One of the challenges is that HTML to PDF conversion is hard, especially when you need superior HTML(5) rendering.
This fast micro-service runs on an Node.js/Express server and caches it's HTML2PDF output for 6 months to reduce it's processing overhead.
Visit the API here: HTML --> PDF API service here.