In order to address the complexity and extensiveness of technology, Cloud Computing is utilized with four main service models. The most recent service model, function-as-a-service, enables developers to develop their application in a function-based structure and then deploy it to the Cloud. Using an optimum elastic auto-scaling, the performance of executing an application over FaaS Cloud, overcomes the extra overhead and reduces the total cost. However, researchers need a simple and well-documented FaaS Cloud manager in order to implement their proposed Auto-scaling algorithms. In this paper, we represent the openCoT platform and explain its building blocks and details. Experimental results show that executing a function (invoking and passing arguments) and returning the result using openCoT takes 21 ms over a remote connection. The source code of openCoT is available in the GitHub repository of the project (\code{www.github.com/adanayi/opencot}) for public usage.