In Spotler Mail+, deduplication rules determine how contacts are uniquely stored in the database. Deduplication rules check during import whether a contact already exists based on one or more fields, such as email address or external ID, and prevent duplicate records or define which data is updated.
What are deduplication rules?
Deduplication rules are settings that define when a contact is considered unique in the software.
A deduplication rule uses one or more database fields to check whether a contact already exists. This can be an email address or an external ID such as a customer number.
When a new contact is imported, the software compares these values with existing contacts. If a match is found, the existing contact is updated instead of creating a new one.
It is possible to configure multiple deduplication rules and apply them in a specific order.
Be careful when adjusting deduplication rules
Changing deduplication rules can have lasting effects on the database.
If deduplication rules are temporarily relaxed or disabled, duplicate contacts may be created. These duplicate records are not automatically merged and will remain in the database.
This can result in multiple emails being sent to the same person, incorrect unsubscribe handling, reduced data quality, and additional manual cleanup work.
Temporary changes are often not reverted, causing the issue to grow over time.
Recommendation: only adjust deduplication rules when necessary and always assess the impact beforehand.
Which topics are covered?
On this page, the following topics are covered:
- Deduplication based on email address
- Deduplication based on external ID
- Using multiple deduplication rules
- Frequently asked questions
How does deduplication based on email address work?
Deduplication based on email address means that each email address can only exist once in the database.
When a file is imported and the same email address appears multiple times, only one contact is stored. The data from the last occurrence overwrites the existing data.
This prevents multiple emails from being sent to the same address and keeps the database structured.
How does deduplication based on external ID work?
Deduplication based on external ID uses a unique identifier to distinguish contacts.
An external ID can be a customer number or membership number and is commonly used when integrating with an external system.
This method is suitable when multiple individuals share the same email address but need to be contacted separately.
For example, multiple family members may use one email address but still need to receive personalized communication. Deduplicating on external ID ensures these contacts remain separate.
How does using multiple deduplication rules work?
It is possible to combine multiple deduplication rules and define their order.
The software evaluates the first rule and then proceeds to the next. For example, it may first check for duplicate email addresses and then for duplicate external IDs.
The order determines how duplicates are identified and processed, directly affecting how contacts are stored and updated.
Frequently asked questions
I changed my deduplication rules. Can I revert this?
Deduplication rules can be reverted, but this only applies to new imports.
Existing duplicate contacts created during earlier changes will remain and must be cleaned up manually.
What should I do if I have duplicate contacts?
Duplicate contacts are not automatically merged and must be manually removed or cleaned up.
When should I use an external ID instead of an email address?
An external ID should be used when contacts must remain unique even if they share the same email address.
This is relevant when integrating with external systems or when multiple individuals use a single email address.
What are the risks of changing deduplication rules?
Changing deduplication rules can result in permanent duplicate contacts, increased maintenance effort, and reduced data reliability.
Always evaluate the impact before making changes.
What is the result?
With correctly configured deduplication rules, the database remains consistent, duplicate contacts are prevented, and data is updated in a controlled manner.