Will a duplicate lead/contact be added in CRM through the Card Scanner App?

Will a duplicate lead/contact be added in CRM through the Card Scanner App?

If the lead/contact already exists in CRM, then while saving the record in the Card scanner app you will be prompted to merge the records. 

Also, note that email address is considered as an unique field by default, so the records will be skimmed for duplicate entries using the email field.

However, if a duplicate record happens to enter your CRM account, you can use either ways to remove them:  

1. The find and merge option can be used if you are specifically looking for duplicates of a particular record. For example, you know that a lead name "David Smith" has been duplicated and want to find duplicates and merge it.
   
2. The deduplication tool can be used when you are not clear if there are duplicates and you want CRM to run a duplication check based on certain unique fields.