Hi, I received a reply from the Testrail support. I asked how to make faster uploading of the test results
Thank you for your email. I am not certain, if there is anything specific in TestRail that would support multithreading.
With TestRail Server, It is my understanding that you would hit the rate limit quickly as the concurrent API processes will create thousands of new test cases each day.
Technically, In my opinion with TestRail Server, the high number of daily uploads via API wouldn't be supported. Also, it would not be recommended since each new test case creation is processing a lot of actions in the database, and running multiple test case creations simultaneously is going to slow the whole process down.
You can find additional information about accessing API by clicking on the link given below:
I hope this helps. Please let me know if you have any further questions or concerns.