Whatsapp Online Tracker API

I just want whatsapp online status tracking API or script. Let me know if You have idea about find API for it and You able to do it. API should be simple input is a phone number with country code - output should be online offline status. I want to check multiple phone numbers. It might use some short of script to detect phone number is online or not. I want full source code. Also bid Your final amount for make application, so I can decide to contact You or not.