WhatsApp Bulk Marketing Sender Tool

I need a lightweight tool that lets me push out promotional text messages to large groups of WhatsApp contacts quickly and reliably. The core flow I’m after is simple: upload or paste a list of numbers, compose a message, hit send, and watch the campaign go... (Budget: ₹750 - ₹1250 INR, Jobs: API, Automation, C# Programming, JavaScript, PHP, Software Architecture, Software Development, Web Development)