Creating new fields in CMS with Webflow API

I have a database of data in Firebase and I’m currently trying to use cloud functions to import the data into Webflow CMS. I’m currently getting an unknown error that I think is because I haven’t defined any fields in the CMS editor on my site. This is because the fields will vary for each item I upload. Can I create fields on each item through the Webflow API?

Nope. FIelds in a collection apply to all items in the collection.