Contact Import Issues: Deduping, Formats, and Country Codes
The three reasons contact imports fail, and how to prep your CSV so WaSMS imports cleanly.
You export a contact list from wherever it's been living — a spreadsheet, an old CRM, Google Contacts — upload it to WaSMS, and get an error, or worse, half your contacts import with broken phone numbers. Most contact import failures come down to one of three things: the file format WaSMS expects, missing or wrong country codes on phone numbers, and duplicate contacts that conflict during the same import. Fix these three before you upload and the import goes through clean almost every time.
The CSV Format WaSMS Expects
WaSMS imports a standard CSV with a header row. At minimum you need a name column and either a phone or email column — you don't need both unless you're reaching the same contact across multiple channels. Here's a minimal template:
name,phone,email
Sarah Ahmadi,+14155550123,[email protected]
Dr. Lin Chen,+442071234567,[email protected]
Every row needs the same number of columns as the header, and phone numbers need the + and country code — see the next section. If you're pulling contacts from Google Contacts, its default export includes dozens of extra columns; delete everything except name, phone, and email before uploading, since extra columns with inconsistent data are the most common cause of a failed row.
Country Code Rules
A phone number without a country code is ambiguous — WaSMS can't tell if a partial number is missing its area code or is genuinely incomplete. Every phone number needs the full international format: a +, the country code, then the number, with no spaces or leading zeros where the country code replaces them (a UK number written locally as 07911 123456 becomes +447911123456).
If your source list mixes local and international formats, run a find-and-replace pass in your spreadsheet before export rather than fixing it row by row after an import error.
Dedupe by Phone or Email
WaSMS treats a contact as a duplicate when the phone number or email matches an existing contact exactly. If your file has the same person twice — once from a WhatsApp CRM export and once from a manual list — the second row either merges into the existing contact, filling in blank fields, or gets skipped, depending on the merge setting you choose at import time. Always dedupe within the file itself first: sort by phone number in your spreadsheet and remove exact repeats before uploading.
Common Contact Import Errors
The three we see most:
- "Invalid phone format" — missing
+or country code. Fix as above. - "Row column mismatch" — a comma inside a name or address field (like "Chen, Lin") breaks the CSV structure unless it's wrapped in quotes. Wrap any field containing a comma in double quotes.
- "Duplicate skipped" — not actually an error, just a notice that a row matched an existing contact and was merged or skipped per your setting.
Re-import Safely
If an import partially fails, WaSMS shows a downloadable list of the rows that didn't go through, with the reason next to each one. Fix just those rows and re-upload that smaller file rather than re-running the whole list — this avoids creating duplicate entries for contacts that already succeeded. Once your contacts are clean, they're ready for bulk sending or bulk WhatsApp messaging without further cleanup.