How Many External ID Fields Can I Create Per Object in Salesforce

This article explains how to request an increase to the maximum number of External ID fields allowed per object in Salesforce. External ID fields are used when integrating with external systems to match records without using Salesforce IDs. Common scenarios include data migrations where records need to be matched by an external system's unique identifier, integrations with ERP or billing systems that maintain their own record IDs, and upsert operations that rely on External IDs to prevent duplicate record creation.

External ID fields must be custom text, number, or email fields. They are indexed, so selective filters on them run quickly, and they can be used with the upsert call to match records during import or integration.

Available Editions:

All Editions

Limit Details

Default Limit: 25 External ID fields per object

How to Increase:

Submit a limit increase request with Salesforce Support

Prerequisites:

Review the current number of External ID fields on your object and confirm you have reached the limit of 25 before submitting a support request. Prepare your Organization ID and a description of your business need before contacting Support.

When Unable to Mark a Custom Field as External ID

1. Make sure there are fewer than 25 External ID fields on the object.
2. If there are already 25 or more, you will need to log a limit increase request with Salesforce Support.

Notes:

• When a field has been designated as an External ID, it is also indexed.
• The maximum number of custom indexes per entity is 25, by default