Create web app using google app script

Hello! First of all thank you for very detailed specification, not often here publishes projects with such a good description. But one important point remained unclear for me. Do you want to use GCP (Google Cloud Platform), SaaS/PaaS/IaaS? Or you want "standalone" web service (front-end, back-end). After I receive an answer to this question, we will be able to discuss the implementation. Thank you for attention!

Dear sir I have Google api expert with an prior experience of Php frameworks Please initiate further for better understandings

Ready to start the work to Create web app using google app script, We can discuss more over chat, Thanks Regard Arjun S.