I need to create a website using Squarespace platform. I want to write a backend service calling a third-party API for some metadata.
I looked in their help center, but I found documentation only for JS, HTML and CSS development.
Do you know if it's possible to create such a service and if yes - what language should be used?
Squarespace doesn't support any server-side/back-end code; it only supports the front-end addition of HTML, CSS and Javascript within Code Injection, Code Blocks, and Developer Mode. Therefore, you'd need to use front-end JavaScript development in order to utilize third-party APIs.