Plumbing Purchase & WhatsApp Portal admin panel also

I run a busy plumbing-supply shop and need a small web portal that makes every new purchase entry worth more than a line on paper. Here is the flow I have in mind: the counter staff open the site, record the item name and quantity, note the supplier and the exact purchase cost, then hit “Save.” As soon as that happens two things must occur automatically: 1. The system stores the entry so I can search, filter or export it later. 2. A WhatsApp Business message is fired off to a pre-defined contact list—filtered by the product category we’ve tagged—letting customers or team members know fresh stock has arrived. Only the “new purchase entry” event should trigger these notifications; low-stock or scheduled reports are not required right now. I still want the flexibility to group contacts into categories so that, for example, only the ‘PVC Fittings’ customers hear about a PVC delivery, while copper buyers are told about copper. Core screens I expect: • Secure login • Simple purchase entry form (item, supplier, cost, quantity, category tag) • Contact/Category manager for WhatsApp lists • Purchase history table with basic search and date filter • Settings page to edit the WhatsApp template message Tech is up to you—PHP-MySQL, Node-Postgres, or any modern stack is fine as long as it is responsive and can integrate with the official WhatsApp Business API (or a reliable gateway) for bulk messaging at reasonable throughput. Deliverables: • Fully functional, browser-based application hosted on my server • Source code with clear installation instructions • Quick user guide showing purchase entry and WhatsApp blast in action If this matches your skill set, let’s talk timelines and the milestones needed to roll it out smoothly.