@tempuralo You’ll need to provide more detail, nobody could answer these questions.
Are you talking about a 3rd party API?
or an API that you’ve created and are hosting on Netlify?
If you’re asking about a 3rd party API you’d be better off asking them.
If you’re asking about an API you created, you’d be better off asking whoever created it, or reading the code.
What ‘proxy server’ are you talking about?
If your Netlify site is important, provide the netlify site name, or netlify.app url.