Hi. I am gonna build a simple app for a company to ease their work. The company is sending out pdf files to their users' email. The data is a health analysis with a lot of different health values. The app should be an MVP, where users can watch their data instead of opening a pdf file. The company should be able to fill in the data in either Firebase or Contentful database. Is Contentful or Firebase best for this solution? What is your opinion?
Generally, I recommend not putting personally identifiable information (user information) into Contentful. If you believe the user information is not personally identifiable (emails are not stored, no full names, etc...) then you could do this in Contentful.
However once you have PII - use a combination approach.
Personal information and health records in Firebase, generic words and language and images in Contentful.
As far as I know, Contentful (I never used it) provides a UI where you can manually manage your data (create, edit, remove data).
You say this:
The company should be able to fill in the data in either Firebase or Contentful database.
My point is that Firebase does NOT provides a User Friendly UI for filling data. You need dev-knowledge in order to use the UI of Firebase Firestore. I would recommend to check how is the UI of Contentful. Spend some hours checking how to manually enter data in Contentful. If you think it's user friendly, so go for it, because Firebase is 0% user friendly.
But, if you want to create your own form for entering the data, and saving it in contentful or firebase... Well... That's another question.