1. Prepare an authorized list
Use contact data you are permitted to process and keep the input limited to fields needed for the checking task.
2. Normalize and test
Add country calling codes, remove blank rows and duplicates, then test a small sample before the full list.
3. Run a paced task
Choose an observable interval and monitor WhatsApp Web. Pacing does not guarantee freedom from restrictions.
4. Interpret and export
Separate registered, not-found, and unfinished states; correct formatting issues; then export the minimum fields required for the next step.