How to Deduplicate WhatsApp Numbers: Normalize to E.164 First, Then Deduplicate by Canonical Number

The same phone number can appear as different text forms with spaces, plus signs, 00 prefixes, or local leading zeros, so direct text comparison misses many duplicates. This article explains the practical order of operations: keep the original column, clean symbols, unify prefixes, add country codes, validate length, deduplicate by canonical number, and retain a mapping table before submitting for verification, reducing verification costs from duplicate rows and making it easy to write results back to each original record.