WhatsApp Chat Admin Management Tool

I need a dedicated application that lets me handle WhatsApp conversations more efficiently. The core of the job is to build a chat-admin tool that works both on desktop and mobile, with separate dashboards for an admin account and any number of moderator accounts... (Budget: $250 - $750 USD, Jobs: Android, API Development, App Development, Mobile App Development, MySQL, PHP, React Native, User Interface / IA)