Best integration strategy advice for a React app (JavaScript)

I have a React app using three.js and would like to support 3D formats that it does not have a loader for yet. I can have backend logic that I call (then spawn off a python process or whatever is needed to do the file conversion), or directly call a web service from JavaScript in the browser. I was wondering what approach you would recommend?

Do you have a web service I could call from JavaScript in the browser? Would it be secure (or would it be too easy for people to watch the API calls and steal keys).

Otherwise I assume I would have to buy a Python API library and call that code from a web service I host? (I would then use my own authentication to stop others calling that API as a free service I pay for.)

Any general advice on which way would work better? Still exploring options

@alan.kent

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@alan.kent
Thank you for sharing that information.
Hosting your own web services would be a better option if you require more control over the security and functionality of your application.