Bulk WhatsApp Broadcasting Panel Development

I need a straightforward panel that lets me broadcast WhatsApp messages in bulk without getting lost in complicated menus. The core task is simple: I upload a contact file (CSV or Excel), type or paste my message, attach any images or videos I like, hit send, and the system delivers everything quickly and reliably.

Key needs
• Message broadcasting is the main workflow—no chatbot or drip-campaign logic required.
• Full multimedia support: photos and videos must go out exactly as they look in WhatsApp.
• Contact management stays manual, so an intuitive import/export screen is essential (drag-and-drop or browse-to-upload is fine).

Deliverables
1. Web-based or desktop panel, fully functional on delivery.
2. Source code plus a brief setup guide so I can reinstall on another server or PC.
3. A quick user manual showing how to upload contacts, compose a message, attach media, and launch a broadcast.
4. Test run proving successful delivery of a small sample campaign.

If you already have a stable solution or can build one quickly with the official WhatsApp Business API, yowsup, Chat-API, or another proven stack, let me know which approach you prefer along with any sending limits or device requirements.