Matching rules versus duplicate rules
Key Takeaway
A matching rule decides which records are duplicates. A duplicate rule decides what happens when a user creates, clones, or edits a record that matches. With the Allow action, the user gets a warning but can still save the record.
Salesforce uses two kinds of rules together to keep duplicate records out of your data. A matching rule compares the fields of records to decide which ones count as duplicates. A duplicate rule decides what happens next, such as warning the user, blocking the save, or reporting the duplicate.
What each rule does
A matching rule answers "are these two records duplicates?" by defining which fields to compare and how. A duplicate rule answers "what should happen?" when a user views a record that has duplicates or starts creating a duplicate record.
A matching rule does nothing on its own. Before an active matching rule can act, you pair it with a duplicate rule or a duplicate job. A duplicate rule runs when a user creates, clones, or edits a record. A duplicate job finds duplicates across the whole org.