Following is a Postman Collection which I need to use for a task management application. Where each user can add, update, and delete his tasks. I’m confused how to use this collection. Would I need a backend or without that? I would use redux-toolkit for state management and local storage for user sessions. What is the use of this collection?

I need to send 1.5M API calls to add something to our customers. I want it to go as fast as possible. We are in AWS. I tried POSTMAN and it actually does good for a 3 hours, then I think it crashes. Does anyone know a tool that will let me do this?