This is a known behavior our engineer team of BIM 360 wanted to share:
If you have not accessed BIM 360 API until you have used BIM 360 Docs for quite a long time, the response time of API invoking would probably be slow when it is the first time you access API. The response time depends on the files volume and the complexity of the structure of the hierarchy. i.e. the response time is directly proportional to the projects complexity and files volume.
1. if files volume is much small, the response is fast. e.g. if an account has a project that contains many folders, but all of them are empty, the response is very fast.
2. if an account has projects that contain many folders, and all folders have many files , the response will be slow.
Our engineer team will work to improve it.