Founders/ Managers/ Operational Heads etc..

What is your A. Product/Service B. Tool that you use to get your Analytics (CPI, Retention, and all the rest) of that product or service? Also, it would be great if you could let me know and any other reader that finds this post that, what are all the metrics you measure, from testing pre-release to full production. I am Karanveer and Thank you for your time.