Cross-Audience Deduplication in Mailchimp

Deduplicate leads and contacts

How to Merge Duplicates Across Audiences for Streamlined Email Marketing

Email marketing effectiveness relies on delivering tailored messages to the right audiences. However, when Mailchimp contacts are spread across multiple audiences, duplication can occur, leading to redundant messages or missing context from previous communications. This can negatively impact complex customer journeys involving different business aspects or sales funnel stages.

Insycle's Merge Duplicates module solves this problem by allowing you to deduplicate within a single audience or across Mailchimp audiences effortlessly. It offers flexible deduplication using any data field, not just email addresses, and automatically deduplicates across audiences by default unless you specify to work within a specific audience. This streamlines your email marketing efforts, ensuring contacts receive relevant communications without redundancies or missing context.

Process Summary

  1. Set rules to identify duplicates.
  2. Review and analyze the identified duplicates.
  3. Choose Bulk Mode.
  4. Set rules to select the master record and determine what field data is retained.
  5. Deduplicate your records.


Step-by-Step Instructions

Step 1: Configure Rules to Identify Duplicates

Navigate to Data Management > Merge Duplicates, pick the record type, and explore the default templates for a pre-built solution.

Insycle offers a flexible way to identify duplicates using any data field, not just the email address. Step 1 looks through the records in your database, examining the fields that you specify for a match.

Click the + Field button to add fields you want to look at for duplicates, along with some parameters on what to look for. You want to choose fields that, in combination, give a high degree of certainty that the matched records are duplicates. See the Advanced How-Tos for more details.

For example, you can try and identify duplicate contacts using the First Name, and Last Name, and Email Address fields. Contacts will need to match all three criteria to be considered duplicates. 

This will identify duplicates across audiences while ignoring the subdomain and top-level domain. For example, it matches with and


Step 2: Analyze the Identified Duplicates

When two or more records represent the same contact based on your matching rules, they are clustered together into duplicate groups. Each duplicate group shows the total number of records that were identified as duplicates based on your settings. For example, if you had four records for the same contact, it would count as one duplicate group with four duplicate records.

Under Step 2, each row represents a duplicate group, with the number indicating how many duplicate records were found. When you click a row, it expands and shows the duplicate records in the group.


Step 3: Choose Whether to Merge in Bulk or Manually

The most efficient and sustainable way to merge duplicates is in Bulk mode. This allows you to set rules for determining the master record automatically across all records in your database. You'll be able to use saved templates and recipes to repeat the process on a regular basis. 

In Manual mode, you have complete control over which records are merged together by selecting them from the Record Viewer. Manual mode should be reserved only for cases where you need a careful, controlled process. Learn more about merging duplicates in Manual mode.


Step 4: Set Rules for Master Record Selection and Data Retention

After selecting Bulk mode in Step 3, you need to define how all of the matching duplicate groups should be merged at scale in Step 4.

Configure Rules to Automatically Select the Master Record

First, select the matching method—Priority Match, or Absolute Match. Most de-duplication operations should use Priority Match. Learn more about these options in the Advanced How-Tos below.


On the Record tab, you define how the duplicate groups should be merged at scale by creating rules that tell Insycle how to select the record from each group to become the master. The master is the record that will remain after the merge.

For example, if you had four records representing the same contact, they would make up one duplicate group with four records, all of which would be merged into one master record. The other three records would no longer exist.


Configure Rules That Determine Values to Keep

Duplicates may be exact match versions of another record, but often there is only partial data overlap between them. When data is split between two different records, both may contain unique and important information you'd like to keep.

Under Step 4, click the Fields tab. For each field you want to control the data retention for, you need to select a Field and tell it where the data for the field should be taken from. This is merged into the master. Any data that is not in the master or not copied to the master is removed.


Learn more about configuring data retention and master record selection.

Step 5: Preview Report and Update CRM

Preview Merged Changes in CSV Report

Now with the filters and master record set up, you can preview the changes you are making to your data. That way, you can check to ensure your deduplication configuration is working as expected before those changes are pushed to your live database. The CSV report that Insycle generates includes records from all the duplicate groups.

Under Step 5, click the Review button and select Preview mode.


Click the Next button to go to the Notify screen, where you can select recipients for the email report and add additional context.

On the When tab, click the Run Now tab, and select which records to apply the change to (in most cases this will be All), then click the Run Now button.


Insycle will generate a preview CSV and send it to your email. Open the CSV file from your email in a spreadsheet application and review the data.


The Duplicate Group ID indicates which records will be merged together.

The Status column indicates:

  • Duplicate – The record is part of a duplicate group.
  • Master The master record chosen for the duplicate group based on default behavior and your Record rules. Review the selections in this row to determine whether the appropriate records are being chosen.
  • Master (After) – This appears only if at least one or more fields have been specified in Step 4 on the Fields tab. For each duplicate group, the Master (After) row shows the values the final record will contain based on your Field rules and the default behavior. 
  • Error – If Insycle is not able to determine which record would be the master, an error message will appear here. See the Troubleshooting section below for more details.

If everything looks good, return to Insycle and move forward with applying the changes.

Save Templates and Setup Automation

After you've seen the results in your CRM and are satisfied with how the operation runs, you can save your configuration as a template, and set up automation so this merge operation runs on a set schedule. If you have several templates you'd like to run together automatically, you can create a Recipe.

By automating with a template, you'll save time and ensure that your duplicates are merging consistently on an ongoing basis.

Return to the Template menu at the top of the page and click Copy to save your configurations as a new version of whatever template you started with. Then click the pencil to edit your new template name.


Under Step 5, click the Review button, and select Update mode.

On the Notify tab, select the send option appropriate for your automation: Always send, Send when errors, or Do not email.

Add any additional recipients who should receive the CSV (and make sure to hit Enter after each address). You can also provide additional context in the message subject or body.


On the When tab, select Automate, and configure the frequency you'd like the template to run. When finished, click Schedule.


You can view all your scheduled automations at any time on the Operations > Automations page.

Insycle-Mailchimp Merge Logic

In Step 4, you can specify how field data is merged and retained. For any fields you don't specify Field rules for, Insycle's built-in synthetic merge will apply.

By default, data from the master record is kept. When a field value in the master is empty, it automatically picks a non-empty value from the most recently updated duplicate. 

When in doubt about what will wind up in your master records after the merge, add the important fields as additional rules on the Record tab of Step 4. Then use the Preview CSV created in Step 5 to review how the values will merge.


Advanced How-Tos

Step 1: Setting Up the Fields to Find Duplicates

Each row in your matching fields setup is cumulative, so records must meet all of the criteria. For example, looking for records that have the same First Name and Last Name and Phone Number returns only results where all three values are the same.

  The minimum required length for the matching values is four characters or more. Values such as "Joe" or "Ace" will be disregarded.

Field Name Comparison Rule Ignored Match Parts

Pick a field that you think has some duplicate values.

Running a very simple match operation like just First and Last Name is okay for giving you an idea of what you have, but it is too broad to use for reliable analysis and deduplication. There may be legitimate duplicate names–different people with the same first and last name. You need additional, unique criteria to narrow it down.

Choosing Unique Identifiers

Matching duplicates requires unique identifiers—data that is unlikely to be shared by any other record unless it is a duplicate. If you don't use unique identifiers, you are likely to identify unrelated records as duplicates and may accidentally merge them.

Many CRMs match first names, last names, and email addresses. If all of those match, or are similar, you can confidently determine that the record is a duplicate.

Other unique identifying fields that are commonly used in deduplication include:

    • Phone number
    • Domain name
    • Mailing address
    • ID number
Step 1: Matching Using Two Different Fields

Sometimes, you might want to match duplicates using data in two separate fields. For example, you might want to compare your Phone Number field to a Mobile Phone Number field to identify duplicates.

Using the Related Fields feature, you can use two different fields (that contain similar data) as matching fields to catch more duplicates.

You can set up Related Fields in the Advanced tab.


Common Examples of Related Field Matching

Matching Field Related Fields
Phone Number Mobile Phone Number, Company Phone
Email Domain Website, Company Domain
Email Address Additional Email Addresses
Address Company Address
Step 1: Allowing Empty Values When Matching

When using two or more fields to identify duplicates, records can still be considered matches even if one of the field values is blank. You just need to specify which field(s) allow a blank value.

Under Step 1, configure your matching rules in the Simple tab, then click the Conditions tab.


All the matching fields you included will automatically appear with the Value Required in All Records condition selected. Change the condition to Empty Allowed in Any Record to allow empty values for certain fields. You can also use the At Least One Record with Non-Empty condition to help you determine which is the master record. Make sure at least one field remains required and is a reliable unique identifier to ensure the records are really duplicates.


For example, on the Simple tab, you may have the matching fields: First Name, Last Name, and Phone Number. But on some of your records, the Phone Number field may be empty. Using the conditions "Empty Allowed in Any Record," or "At Least One Record with Non-Empty," all records with the same name, same phone number, and no phone number will be considered duplicates.


Step 4: Selecting Priority Match vs Absolute Match


Priority Match: Looks through the master selection rules in order, one by one. As soon as a record meets one of the criteria, Insycle makes the master selection and skips the rest of the rules on the list. The vast majority of duplicate templates should use Priority Match.

Absolute Match: The master record must meet all of the listed rules in the Record tab in Step 4. If a record does not match every rule listed, no master record will be identified. Absolute Match is appropriate for less flexible master selection.

For example, if a company wanted to ensure the chosen master record is in their sales pipeline and already has a sales rep working the record, they can choose Absolute Match and set the Record rules:

  • Lifecycle Stage is lead
  • Contact Owner exists

Choosing Absolute Match can often result in no master record being identified since the record has to match every rule listed, so in most cases, you should select Priority Match.

Step 4: Understanding Master Record Selection

Let's say we have four records that represent the same person—Marta Vaskovitch. The Merge Duplicates module will identify this as one duplicate group consisting of four records.

Here is the data that we have for this duplicate group:


Here are the master selection rules we have set up:


We haven't sent any emails to Marta yet, so when Insycle processes the first three rules—Marketing emails clicked, emails bounced, and emails opened—Insycle cannot eliminate any record because they all have the same value of zero.

In the next rule about contact owner, records 61301, 61201, and 61251 are eliminated since no contact owner exists for those records. Now, only one record remains, 61351, therefore that's the master record.


Step 4: Data Retention Setup Examples

The master record can use values from several different records from the duplicate group, based on the rules that you set in the Fields tab under Step 4. 

By default, any fields not specified here will use the master record values. However, if the master field is blank, the value from the most recently updated duplicate will be used.

In this first example, the Ownership value from the record with the most recent Modified Date will be kept, and all the Account Owner values from the records in the duplicate group will be saved to the Merged Owners custom field.


In this example, the most recent interaction data for several fields will be used in the merged record.


In the example below, six master field rules have been set up, including two different rules for the Lifecycle Stage. Insycle will look at the first of the two, and if it finds a record that matches the criteria, the second Lifecycle Stage rule will be ignored. In the example, if a record in the duplicate group with the "Lifecycle Stage" of "Customer" is found, then the next rule looking for the "Lifecycle Stage" of "SQL," would be ignored.


Granular Control for Picking Duplicate Records

For situations where there are no common rules you can apply for identifying duplicates for all or some of the records, you may need more granular control for picking records to include or exclude from the process. In these cases, you can use CSV files to customize your bulk merging, designate master records, and exclude records from deduplication. Then you can import the CSV from the Magical Import, and use the Merge Duplicates module for complete control over the final merge operation. Learn how to customize merging Duplicates in bulk using a CSV.

Tips for Bulk Merging Duplicates

  • Begin with easy-to-find duplicates. Iterate through fields and rules you know will surface duplicates. Don’t expect to resolve all your duplicates by setting up and running this process once. You will need to run this process multiple times for different fields or nuanced variations.
  • Each time you get a Merge Duplicates process to run the way you want in your database, save it as a template. When you have a solid set of templates that reliably resolve most of your dupes, you can put them together as a Recipe that can run on a regular, automated schedule.
  • You may also need to look for edge cases that fall outside your standard rules. These may be templates you run manually so you can make adjustments based on what you find.
  • Do some experimentation. Use the Preview mode CSV report to analyze patterns in the duplicates. You may learn what is causing the duplicates and learn how to avoid having them in the first place. You may also want to explore your data in the Grid Edit module to understand what you have so you can design templates that catch all potential variations.


If you're not seeing the results you expect when merging duplicates, consider these issues:

Not all identified duplicates are merging into the master

You have duplicate records that have been identified by Insycle but not all of them are merging into the master. Under Step 2, check to see how many duplicates are in the affected duplicate groups. If you have duplicate groups that contain more than five records, you may want to change the value in Skip duplicate groups with more than 5 records per group to make sure you can get them all.


This setting is intended to protect against the accidental merging of non-duplicate records if the filter in Step 1 is too broad.

Message in CSV, "Change rules in Step 4 'Master Selection'" 

If the Message column of the CSV report displays this text:

Change rules in Step 4 'Master Selection'. Failed to pick master record because multiple records (X) meet the selection criteria. In 'Master Selection', change, add, or reorder the rules such that only one record matches (if cannot determine master based on field values, use 'Record ID is lowest' as the last rule).


This means that based on all the rules, Insycle could not figure out which record in the duplicate group would be the master. None of the records meet more of the rules than others.

There are a few things you can try to resolve this:

  1. Under Step 4, on the Record tab, experiment with reordering or adding additional fields that are likely to have unique values.
  2. In the Step 4 heading, check to ensure that you have Priority Match selected and not Absolute Match.

    With Priority Match, your master record only has to match one rule. Using Absolute Match, your master record would have to meet all of the rule criteria. The majority of the time, it is best to select Priority Match.

    If Priority Match was used, then none of the records in the duplicate group meet any of the criteria on the list more than the others. In this case, you'll need to experiment with the Record tab, reordering or adding additional rules for fields likely to have unique values.

  3. As a last resort, you can add a rule on the Record tab of Step 4 that says Record ID is lowest, or Create Date is earliest.
Non-duplicate records are being merged together

There are a couple of things to look at that may be misidentifying records as duplicates.

First, you may need a better unique identifier. Under Step 1, if you only use fields that could correctly contain the same values in multiple records, these aren't unique identifiers. In this case, you are likely to identify unrelated records as duplicates and may accidentally merge them.

Unique identifiers are data that is unlikely to be shared by any other record unless it represents the same underlying entity. Fields that are commonly used in deduplication include phone numbers, email, mailing addresses, or ID numbers.

Second, this may indicate the Comparison Rule under Step 1 is too broad. Try using the Exact Match comparison rule instead of Similar Match. Similar Match looks for values that may be close but with a one-character difference (maybe a typo) which broadens the search. 

Remember, always run your deduplication in Preview Mode to confirm things are working as expected before running them in Update Mode and applying the changes to your Mailchimp records.

Insycle isn't finding any duplicates

Most of the time, when Insycle can't find duplicates, it is due to your matching rules in Step 1. It is important to analyze the underlying data to better understand how to set up your rules. A useful exercise can be to set up your matching filters to look for exact matches of just First Name and Last Name


When you click Find, these rules can show you a broad overview of what duplicates are potentially in your database and what fields might be useful to include in your matching fields. These settings are just for discovery and should not be used for a final merge operation; many people can have the same first and last names and are not duplicates. 

To get further context, in Step 2, click the layout gear button on the right side of the title bar. Here, you can add any field in your database as a column to the duplicate group review to better understand the data inside these records.


For more help troubleshooting issues with Insycle, refer to our Troubleshooting Issues article.

Frequently Asked Questions

How do I ensure that I am not merging non-duplicate records together?

There are two ways to make sure that the records that you are merging are indeed duplicate records.

First, always run your deduplication templates in Preview Mode before running them in Update Mode. This produces a CSV that shows you how your records would have been merged. Then you can ensure that your Merge Duplicates template is working as expected and not merging non-duplicate records together.

Additionally, to ensure a smooth merge process, consider narrowing down the matching settings in Step 1. Try the Exact Match Comparison Rule instead of Similar Match. Then make sure that you are using actual uniquely identifying fields—first name, last name, email, and phone number are popular choices. The more tightly defined your filter is, the less likely you are to merge non-duplicate records.

I already have a list of duplicates, can Insycle bulk merge them?

Yes. You can use an existing CSV with duplicate record details. The file needs to include the record IDs and a "Deduplication Master" column, specifying which records should be the master, kept after the merge. Next, create a custom field "Deduplication Master" in your CRM to facilitate the merging. Use the Magical Import module to import the edited CSV file into the CRM, populating the new custom field. Finally, utilize this custom field to merge the duplicate records in the Merge Duplicates module.

Learn more about customizing bulk deduplication from a CSV.

Can I select which data is retained in my master record on a field-by-field basis?

Yes, Insycle allows you to select which field data is retained in the master record using the Fields tab under Step 4. See the section, Step 4: Set Rules for Master Record Selection and Data Retention of this article for more details.


I need to exclude some records from deduplication. Can I do that?

Yes. You can exclude records from deduplication by creating a CSV with a "Deduplication Exclude" field.

First you'll export a Preview CSV from the Merge Duplicates module, add an exclude column, and specify which records should be excluded from the merge process. Next, create a custom field in your CRM to facilitate the merging. Use the Magical Import module to import the edited CSV file into the CRM, populating the new custom field. Finally, utilize this custom field to merge the remaining duplicate records in the Merge Duplicates module.

Learn how to customize bulk deduplication using exclusions.

Do my matching fields have to match each other exactly?

No. The Similar Match Comparison Rule found in Step 1 looks for values that may be close but with a one-character difference (maybe a typo) and broadens the search. This search behaves like when Google shows results for a slightly different term, or says “Did you mean...” For example, if a Company Name of, “Acme” is found, it could include records with the Company Name values “Akme, acm, Acma,” etc., as a match.

You should be careful when using Similar Match as the looser criteria can incorrectly identify non-duplicates as duplicates. 

Review the Understanding Similar Matching best practices for more detail.

Why can I only process 50 duplicate groups at a time?

Insycle shows 50 records on the module screen as a preview; this isn't the entire list of records. To see everything, include all records when you view the Preview CSV report.

Insycle can process thousands of duplicate groups in one operation. Potentially, you could deduplicate your entire database in one operation. 

How many duplicates can I merge into one master record?

You can merge up to 100 duplicate records into a single master record. 

If you have duplicate groups that contain more than five records, you may want to change the value in Skip duplicate groups with more than 5 records per group under Step 3 to make sure you can get them all.


This is a precaution to ensure that if you use a duplicate matching filter that is too broad in Step 1, you do not accidentally merge many non-duplicate records together. If you are going to set this number at a high level, it is a good idea to run Preview Mode first to make sure your deduplication template is operating as you intend.

Are there any limits on the number of records that can be identified and merged with my paid subscription?

All plans include unlimited usage, unlimited users, and unlimited operations. See the pricing page for more details. During the free trial, there is a cap of 500 records updated, cleansed, or merged.

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