We're using the content api in Umbraco 13 (Cloud) and render it in a completely standalone SvelteKit-frontend. Now I want to utilize the members and the content api to create a login, is this possible and how would one go about doing so?

See [Protected content in the Delivery API](https://docs.umbraco.com/umbraco-cms/reference/content-delivery-api/protected-content-in-the-delivery-api) which should help. I've not used it myself though.