The last modified by field displays which collaborator made the most recent change to a record. 

When a last modified by cell is empty, this is due to one of three reasons.

1. No users have yet made any modifications.
2. The record predates the last modified by feature.
3. The base has been copied from a template or other base.

Customizing the last modified by field

The last modified by field is added from the field configuration menu. You also may be interested in using the last modified time field to track when a change was made.

By default, the field will return the name of the collaborator who last modified any field for that record. You can also limit which fields the last modified field "watches" by clicking the "Specific fields" option and choosing one or more fields in the table.

After confirming the selected fields, the field customization menu will show the specific fields you've chosen. You can edit your selections by clicking the Change selected fields button.

Last modified by field behavior with other fields

Computed fields (formulas, lookups, rollups, and counts)

The last modified by field reflects changes in fields where you can make edits.  This means that fields computed by Airtable such as formula, created time, and rollup fields will be ignored if their values change.

If the computed field relies on a value you edit, you can set the last modified by field to watch the fields referenced by the computed field.  For example, if you have a formula with {Quantity} * {Unit Price}, then the last modified field can be limited to just the Quantity field and the Unit Price field.

Linked record field

The last modified by field will change if you add and remove a record from a linked record field. For example, if you add another furniture item to the "Order line items", the last modified by value will be updated to show you as the most recent collaborator to make a change.

Items added or removed from a linked record field will display someone for the last modified field in that record.

If the displayed name of an item in a linked record field is modified, the last modified field will not change because the record that was changed was in a different table.

However, if you do want the details of who last changed the records in a linked record field, you can still do this by adding a field to the other table (the Order Line Items table in this example) and then adding a lookup field to the original table to pull in the collaborator name.

Last modified by field and blank values

When no cells in a record have a last modified time, the value of the last modified time field will be blank. This can occur for a few reasons.

1. No users have yet made any modifications

When a new blank record is created that has no user-created values, none of the fields will have any collaborators listed in the last modified by field, because no users have yet made any modifications.

2. The record predates the last modified time feature

Last modified by started tracking from when the feature was enabled. (June 2020 is when we officially launched this feature.) Any old records that were in your bases before last modified by was enabled will return blank values.

Any new modifications made to the records will overwrite the blank value with the collaborator who makes the most recent change.

3. The base has been copied from a template or other base.

When you copy a template or one of your own bases, the values for last modified by and created by are removed for the new base as they are new records.

Frequently asked questions

A last modified by field shows I made the change, but I don't remember doing that.

Any record modified using your account information will show you as a collaborator.  This means if you have set up an integration using your API key, all records changes from the integration will be associated with you.  If you would like to make it easier to keep track of record changes through the API, you have a couple of options:

• You can create an Airtable account for the API with a different email and use an API key generated from that account.
• You can add a field named "Source" (or something similar) which you use in an API request to add free text of where the modification came from. The last modified by field won't change to reflect that value, but you could filter on the new source field instead.