I'm a mobile developer and have several shared projects with others where each of us have some expenses and some revenue related to the projects. Right now I maintain a spreadsheet for these accounting calculations.
I'd like to build a subscription-based web app service that would allow users to create a project, invite the other members of the project, and they each add their expenses and revenues in order to calculate their profit sharing.
I've been doing this in spreadsheets on multiple projects with multiple members for over a year, so I have detailed specifications of the accounting calculations involved and how to handle various situations (e.g. when a project is not profitable at all).
I do not have designs, but can refer you to a website that has a design similar to what I would like.
I do have detailed specifications of what I require, and as a software developer myself, I've tried to think through the relationships between different model objects, and what edge cases...