How to merge duplicate customer records

Duplicate customer records happen when the same person books with different contact details, is entered manually by staff, or is accidentally created twice.

Merging combines those records into one customer profile and moves the related data onto the record you choose to keep.
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⚠️ Merges move real customer data

Review both records carefully before confirming. Every merge can be undone for 30 days.
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💡 Requires: the Merge Customers permission, available to Admin and Manager roles by default.

Common causes include:

CaptainBook detects likely matches and shows them as possible duplicates for you to review.

There are three ways to find them.
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Open a customer record.

If CaptainBook has detected possible duplicates, you will see a duplicate count next to the customer’s name.

Open the Possible duplicates tab on the customer record.

CaptainBook shows possible matches for that customer, with the strongest match first.

Each candidate includes a Review or Merge action.

The list loads when you open the tab, so you may briefly see a loading state.

Go to:

Customers → Actions → Duplicate customers

This shows duplicate clusters across the entire business unit and is the easiest way to work through a larger backlog.

The option is only visible to users with the Merge Customers permission.

CaptainBook compares customer records using signals such as:

Phone numbers are normalized before comparison, so formatting differences do not necessarily prevent a match.
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💡 Possible duplicates are suggestions, not automatic decisions.

Two people may legitimately share contact details. Always review both records before merging them.

Click Review or Merge on a possible duplicate.

CaptainBook opens a full comparison page showing both customer records side by side.

The record on the left is Keeping.

This is the customer record that will remain after the merge.

The record on the right is Merging in.

This record will be removed after its data is moved to the surviving customer.

If the direction is wrong, click Swap before continuing.

Choose the record that is more connected to the customer’s existing activity rather than simply choosing the one that looks cleaner.

For example, you may prefer the record that already has:

CaptainBook compares the customer fields from both records.

These include:

The fields are grouped based on whether they need your attention.

Both records contain a value, but the values are different.

CaptainBook preselects the value from the record you are keeping, but you can choose the other value instead.

One record has a value and the other is blank.

CaptainBook automatically keeps the available value.

You do not need to make a choice.

Fields that are the same on both records are collapsed so you can focus on the differences.
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💡 A blank field is not treated as a conflict.

If the customer you are keeping has no phone number but the duplicate does, CaptainBook keeps the phone number automatically.

If both customer records have saved payment information, you choose which complete payment identity to keep.

The card information is treated as one unit, including:

You cannot mix individual payment fields from both records.

By default, CaptainBook selects the card with the later expiration date.

If only one customer has a saved payment method, it is selected automatically.

Before confirming the merge, CaptainBook shows a summary of the data that will move.

This may include:

It also shows the date until which the merge can be undone.

Review this carefully before clicking Merge.

The following data is reassigned from the duplicate customer to the surviving customer:

Where both customers have the same segment membership, the duplicate membership is removed.

Where custom attributes exist only on the duplicate, those values are preserved.

Some records intentionally remain where they are.

Historical membership records are not rewritten, so past audience-growth reporting remains consistent.

These are intentionally left in place.

On the next sync, the duplicate customer’s identifiers are removed from Google or Meta and the surviving customer is added correctly.

These are not reassigned during the merge.

Merging customers does not:

The merge happens silently in the background.

After merging, you return to the surviving customer record.

A banner at the top of the record shows the merge status.

You may see:

The main customer data has already moved, while timeline activity is still being transferred in the background.

This normally only takes a short time.

The merge has completed successfully.

You can undo it for 30 days.

The merge itself completed, but part of the background process may have failed.

Contact support if you see this status.

For 30 days after a successful merge, the Merged banner includes an Undo button.

Undo restores:

Undo does not reverse everything that happened after the merge.

For example, it cannot undo:

After 30 days, the stored merge snapshot is deleted and self-service undo is no longer available.
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⚠️ While a merge is still undoable, neither customer record can be permanently deleted.

If several records have been merged into the same customer, you must undo the most recent merge first.

For example, merging three customer records creates two separate merges.

To reverse the entire process:

CaptainBook will prevent you from undoing them in the wrong order.

The duplicate customers queue also lets you process multiple duplicate clusters at once.

Bulk merge uses conservative rules.

CaptainBook:

This means bulk merge intentionally leaves uncertain cases for manual review.

After a bulk merge, CaptainBook reports:

Skipped pairs show which fields caused the conflict.

A failed pair does not stop the rest of the bulk merge from completing.

Start with the highest-confidence matches first.

Exact email matches and cases where one record was created online and the other by staff are usually the easiest to review.

Work in smaller batches, then review skipped records manually.

If two records could genuinely belong to different people — for example, family members sharing a phone number — leave them separate unless you are confident they are the same person.

Customer merging uses its own permission:

Merge Customers

This permission is granted to Admin and Manager roles by default.

It is separate from the standard customer editing permission because merging removes one customer record and moves associated bookings, payment details, and history.

To change access, go to Roles & Permissions and enable Merge Customers for the appropriate role.

No. Merging customer records sends no customer communication.

No. Customers from different business units cannot be merged.

It disappears from your customer lists but is retained behind the scenes during the 30-day undo period.

You choose which saved payment identity to keep.

CaptainBook defaults to the card with the later expiration date.

Yes. During the next audience sync, the duplicate customer’s contact details are removed and the surviving customer is synchronized.

Yes.

From the duplicate customers queue, larger clusters are processed one pair at a time.

From an individual customer record, you merge one pair at a time.

Self-service undo is no longer available.

Contact CaptainBook support with the relevant customer IDs to see what can still be recovered.

Duplicate detection and customer merging are available on:

The feature itself is available on every plan.

What differs is the amount of CRM data available to move.
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On Starter, Extended, and Ultra, additional CRM information such as timeline activity, message history, and attribution can also be associated with the surviving customer.

On Legacy, those CRM records do not exist, so the merge focuses on information such as bookings, guests, documents, payments, and conversations.