I run a field-service operation that looks after more than 500 customers and I want to tighten up the way we organise daily work. The core objective is efficient job scheduling: every booking should automatically slot into a cluster, notify the customer on WhatsApp when the job is scheduled, and feed my technicians their day’s itinerary without any manual copy-paste. Today I already rely on a basic rule-based Google Sheet, so I’m not looking for a full-blown CRM or anything AI-driven. I just need lean, fully explainable Google Apps Script routines tied to the WhatsApp Business API. Here’s the flow I have in mind: • One master sheet lists Customer ID and Cluster ID. • A scheduling sheet assigns jobs and bundles them by cluster or technician. • Whenever a job is scheduled (that event alone), an Apps Script calls the WhatsApp API to send the customer a reminder and tracks the confirmation. • A separate daily digest message goes out to each field tech listing all jobs for that day. Deliverables I expect: 1. Clean, well-commented Apps Script files hosted in my Google Drive. 2. Any helper sheets or custom menus that make scheduling and message triggers easy for non-technical staff. 3. A WhatsApp API connection (Cloud API or your proven alternative) set up and documented so I can re-issue access tokens myself. 4. Quick setup notes and a brief hand-off call. Please include links or brief summaries of past Google Apps Script projects and any WhatsApp integrations you’ve completed, plus an outline cost and timeline to get this live. Lean, reliable code matters more to me than fancy extras.