WhatsApp Invalid Number Handling: Distinguish Three Layers, Clean, Detect, and Write Back to CRM in Order

WhatsApp invalid numbers usually fall into three categories: format errors, numbers not in service, and numbers that are valid but not registered on WhatsApp or banned. This article explains the processing order: first standardize to E.164 locally, then split by country and deduplicate, then perform status detection and group by reason, and finally write back to CRM and regularly recheck. This avoids mistakenly deleting still-usable numbers and avoids paying to detect obviously incorrect data.