How to Clean and Deduplicate Contacts
Duplicate and invalid contacts hurt deliverability and skew your metrics. OutSends provides tools to find duplicates, validate email addresses, and clean your lists automatically.
What you'll need
Before you start, make sure you have the following ready.
- An OutSends account
- A contact list to clean
- An email validation tool (built into OutSends)
Step-by-step guide
Follow these steps to complete the setup.
Run duplicate detection
Go to Contacts > Cleaning > Find Duplicates. Choose matching criteria (email, name, or custom field).
Review and merge duplicates
OutSends groups potential duplicates. Review each group and choose which contact to keep or merge fields.
Validate email addresses
Run email validation on your list. OutSends checks syntax, domain validity, and mailbox existence.
Remove or suppress invalid contacts
Automatically suppress invalid emails. Move unsure contacts to a review list for manual inspection.
Set up automatic cleaning
Enable automatic deduplication on import and scheduled validation runs to keep your lists clean.
Tips for best results
Pro tips to get the most out of this setup.
- Run deduplication monthly for active lists, quarterly for inactive ones
- Merge, don't delete — you might miss important data in secondary records
- Re-validate contacts older than 6 months — email addresses change
Frequently asked questions
How do duplicates get created?
Multiple imports, different signup sources, manual entry errors, and API integrations are common causes.
What merging strategy should I use?
Keep the most recent contact record and merge custom fields from older records.
Can I recover a merged contact?
Yes, OutSends keeps a merge history for 30 days. You can revert merges if needed.
Related guides
Explore more how-to guides for OutSends.
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