If you have a single page application without a backend server for communicating with APS APIs, please continue READing, otherwise, you can leave the page safely :)
Due to security consideration, some of Autodesk APS APIs implemented or going to implement a security improvement, the APIs will not allow arbitrary origin for Cross-Origin Resource Sharing, which means your request will be blocked with an CORS error if the request to APS APIs is directly from Web Browser client, you will find the error as follow in the console of your browser.
It's recommended to have your requests to APS APIs from your own server instead of the client side, or you can use a proxy server if can not build your own, here is a post 3 Ways to Fix the CORS Error — and How the Access-Control-Allow-Origin Header Works
And here is the details about CORS.
If you have any questions or feedback, please contact us through our APS support channel.