Startup Idea: Time Tracking Solution for Project-based Tasks

Startup idea to develop a software that helps consultants accurately track and allocate time spent on various projects by integrating with email platforms, like Gmail or Outlook. The software would leverage APIs to determine time spent on relevant emails, aiding in more accurate charge assignment to specific tasks or projects.

I work for a consulting company and work on many projects at one time. One people we face every time period is trying to determine how much time to charge to a specific pursuit. Software that could provide an estimate for how to do this would be valuable to reduce time spent to do this. My thought would be using gmail or outlook APIs to determine time spent on emails.