What is the best stack use api's without exposing api keys

I have a website that needs to integrate with another service via API and API keys. I also need to use API keys to make them work. what is the best stack to do this. is there a backend service I can use and then connect it to webflow?
Thanks.

Lots of options, but it depends on exactly what stack your API needs.
If it’s doing simple calls and just returning the result, you can use Netlify’s free serverless functions.

I recently built a Youtube playlist integration for a Webflow designer, who needed the site to automatically show the current playlist content & sequence. I wrote both the serverless function ( which calls the API using the API key ), and the client-side code which calls the serverless function and renders the result in TypeScript, in a single github repo, and deployed them together to Netlify.

Very slick possibilities.

its an ecomm platform that has api’s to get data on products and categories and for sending purchase data. that kind of stuff. what would I need to build that

Can’t say, as I’m not the platform engineer on your project.
My guess is you aren’t doing heavy transforms, and probably don’t need Node or other heavy server-side coding, so as I suggested - serverless may work fine for you.