Windows / Mac application for time tracking and making screenshots

I have Time Tracking SaaS website.

I need Windows & Mac application that will track work time.
Similar to competitor: https://tinyurl.com/app/myurls

All requests will be made to my service by already made API.

Some features:
- when clicking start - app sends API request to my API
- when clicking stop - app sends API request to my API
- when work is started app makes screenshots of opened apps every X minutes and sends files by API (proof of work)
- when work is started app counts number of key pressed in every minute and every 10 minutes sends reporto by API to my server
- when work is started and in 5 minutes there is no key pressed or mouse moved - app send information to API

Please bid only if you are experienced with similar projects.
Please write what technology you want to use.

Please don't bid if you don't have anthing to show, only developers, NO agencies(!).