Articles on: Contacts

Duplicate Contacts and Deduping Behavior

Duplicate Contacts and Deduping Behavior


Purpose


What happens when you upload a CSV that contains the same email twice? Or when a contact already exists in the campaign? This article explains how SuperSend handles duplicates on import and what to expect.


How SuperSend Handles Duplicates


SuperSend uses email as the unique identifier. When you upload contacts:


  • New email → Contact is added to the campaign.
  • Existing email → Contact is updated with the new row data. No second contact is created.


You do not get duplicate contacts for the same email. The system updates the existing record with whatever fields you mapped from the new CSV row.



What You See After Import


When the upload completes, the notification shows something like:


"X contacts added, Y updated, Z failed. View reasons: [link]"


  • X added — New emails that weren't in the campaign before.
  • Y updated — Emails that already existed; their data was updated with the new CSV values.
  • Z failed — Rows that couldn't be processed (e.g., invalid email, missing required field). Click the link to download the failure report.



No "Skip Duplicates" Option


SuperSend does not offer a "skip duplicates" or "reject duplicates" option. The behavior is always update on duplicate. If you upload the same email with different first name, company, or custom fields, the contact record is updated to the latest values from the CSV.



Why This Design?


Updating on duplicate lets you:


  • Refresh contact data — Re-upload a list with corrected or enriched fields.
  • Avoid accidental duplicates — Multiple uploads of the same list won't create duplicate contacts.
  • Merge in new columns — Add fields to existing contacts by mapping them in a new CSV.



If You Want to Avoid Updating


If you only want to add truly new contacts and not overwrite existing ones:


  1. Export your current campaign contacts first.
  2. Compare your CSV against that export to remove emails that already exist.
  3. Upload only the new emails.


There is no in-app "add only new" toggle; you control this by filtering your CSV before upload.



Duplicates Across Campaigns


Contacts can exist in multiple campaigns. A contact in Campaign A and Campaign B is not a duplicate — they're the same person in two different campaigns. Deduplication is per-campaign on import. The same email can be in many campaigns; each campaign maintains its own contact record for that email.



Expected Result


You understand that duplicates by email are updated, not rejected. Use the import summary (added/updated/failed) to see what happened. Use the failure report to fix any rows that didn't import.



Updated on: 17/03/2026

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