What Is a Duplicate Rule in Salesforce?

A duplicate rule defines what Salesforce does when a user is about to save a record that looks like an existing one - block it, allow it with a warning, or ju

Updated 2026-09-09

A duplicate rule defines what Salesforce does when a user is about to save a record that looks like an existing one - block it, allow it with a warning, or just report it - based on a matching rule that decides what counts as a match.

In more detail

Duplicate rules and matching rules are two different pieces: the matching rule defines the fuzzy-match logic (close variations of a name, email, or phone count as a match), and the duplicate rule defines the action taken when the matching rule fires.

They operate at save time, on new and edited records. They do nothing about duplicates already sitting in the org - that is an exact-match SOQL audit and a merge, not a rule.

Why it matters for admins

  • They are the prevention half of deduplication; SOQL and merge are the cleanup half. Neither one works well without the other.
  • Salesforce ships standard matching rules for Account, Contact, and Lead that can be activated without configuration.
  • A rule set to Alert rather than Block still lets a duplicate through if the user dismisses the warning, so "we have a duplicate rule" is not the same guarantee as "we have zero duplicates."

Frequently asked questions

Do duplicate rules stop duplicates that already exist?
No. They only evaluate records being created or edited going forward. Existing duplicates need a SOQL-based audit and a manual or bulk merge.
Can a duplicate rule block a save entirely?
Yes - a duplicate rule can be configured to Block, which prevents the save until the user resolves or confirms the match, or to Allow with an alert, which only warns.

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