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Best practices: Profile merging

profile merging best practices with customer data profiles in the BlueConic CDPBlueConic customers can merge profiles that belong to the same visitor or customer. This is a powerful and useful feature but must be used with care and precision. Profile merges help you to unify customer data into a single, full view of the individual. But these merges are also irreversible.

BlueConic best practices for unifying profiles via profile merging

We've collected the following best practices for profile merging from our customers and Customer Success team members.

Build your merge strategy on persistent identifiers unique to an individual that do not change over time

In general, successful profile merging strategies use a persistent identifier that is unique to an individual. Make sure the ID you use to match profiles is unique to an individual and does not rotate over time (as CRM IDs do). Learn more about unique identifiers in BlueConic.

Make sure unique identifiers remain unique

BlueConic helps you ensure a unique identifier remains unique to an individual even when someone updates an email address, shares devices, or forwards your emails. For example, when you designate a profile property as a unique identifier – such as an Email ID – you can enable a setting on the property’s page to create a new profile in the event the identifier changes. For security reasons, using this setting is recommended to help prevent potential profile hijacking:

BlueConic profile merging best practices

Use caution when merging profiles across devices and systems

IDs that are set or changed across channels or devices can affect your merging strategy. For example, an email you send to customers can be opened on multiple devices; if you merge profiles off an ID retrieved from the click URL, and the email recipient forwards the email to ten friends, you run the risk of merging all of their profiles together based on that single ID. To ensure profile merging across devices is set up properly, email link clicks should pass along an identifier (hashed email ID, hashed customer ID, etc.) that is stored and used for profile merging (with strict IP checking turned on).

Note: Even with IP checking turned on, unintended merging can occur for organizations using a VPN.

Use subrules and IP checks to ensure accuracy

Creating subrules for profile merging helps increase accuracy. You can set a level of IP address checks to use during profile merges: no IP check, regular IP checks, or strict IP matching. Review the article Checking IP addresses before merging profiles for details.

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Consider different ways to improve match rates

  • Use data processors to clean up email fields. The email cleansing data processor can be added to fix common typing mistakes in email addresses, which can help increase the addressable audience size and improve the match rate for profile merging.
  • Do as much deterministic matching via profile merge rules before using AI Workbench for probabilistic matching. Review the article Running probabilistic matching in AI Workbench for details.

Be conservative with merge rules to avoid unintended consequences

  • Start simple with just a single merge rule. You can gradually add more merge rules over time, but be conservative with your rules to avoid unintended merges. 
  • If you have multiple merge rules, it can be difficult to troubleshoot which merge rule is resulting in unintended merges.

Tips to remember about profile merging

  • Profile merges are irreversible. You cannot unmerge profiles.
  • Your profiles are built up across devices and channels, so your merge strategy should reflect this.
  • When two profiles are merged, their consent objectives are combined. If one profile has consented to the objective, that setting is preserved.
  • Certain out-of-the-box profile properties have system-controlled merge strategies. See Managing read-only, system-controlled profile properties for details.
  • Your Customer Success Manager can help brainstorm and refine the best merge strategy for your business and your unique customer data.

Precautions for profile merging

BlueConic provides safeguards when purging and merging profiles. Profile cleanup (i.e., purging) and profile merging, both available through the BlueConic Settings menu, can help you eliminate duplicate or less relevant profiles and keep your database organized; they can also help you comply with data retention requirements in different privacy laws.

However, since these tools are activated through defined rules that are irreversible (and apply to both current and future profiles), precautions are in place to avoid mistakes and unintended profile data loss.

For all profile merges, BlueConic imposes:

    • A limit of 24 lookups to check if a profile must merge with another existing profile.
    • A limit of 1,000 merges for a single profile.
    • A four-character minimum for any profile property value used in a merge rule.
    • A maximum of 20 matching profiles for a merge to take place.

Vertical examples of profile merging best practices

Depending on your business model, a variety of unique identifiers might be available for creating effective profile merging rules.


  • As a first step, it’s helpful to have a list of identifiers for consumers available; this can help you inform what merge rules you need. Make sure the identifiers are unique to your consumer and not rotated by other systems you might be integrating with. (Some CRMs rotate the CRM ID, for instance.)
  • Usually a persistent ID is available post-login (e.g., customer ID, hashed ID), which can be used to merge profiles uniquely.
  • Authenticated matches are preferred for merging.
  • Email addresses collected using a form listener or from a query string parameter from an email click are less reliable and may result in unintended profile merging if someone enters a common fake email address in the from (e.g., or if they forward the email address to a friend or colleague.
  • Be mindful if your customer service or support team troubleshoots customer issues by logging in using their username and password. If the customer service or support team member does this, the support team member’s profile will merge with the customer’s. Customer service or support teams should use Chrome Guest Mode or Incognito for testing at times when they absolutely must log in using the customer’s credentials.


  • Usually email address is used or IDs from ecommerce systems (if available)
  • Adding subrules to your merge strategy helps to ensure you don’t accidentally merge the wrong profiles.
  • To increase match rates, you can use Email Address (All) instead of Email Address (Most Recent / Primary) for matching.
  • If your customer loyalty system has a loyalty ID, it can be useful for matching profiles.


  • Media and publishing companies use a mix of email matching rules and customer or subscriber IDs. 
  • Authenticated matches are preferred for merging. This includes email addresses or other IDs that are made available client side (e.g., via JS variable) when a subscriber logs in.
  • Email addresses collected using a form listener or from a query string parameter from an email click are less reliable and may result in unintended profile merging if someone enters a common fake email address in the from (e.g., or if they forward the email address to a friend or colleague.
  • Account sharing is a known scenario that should be considered. If two individuals are sharing the same credentials, their profiles will merge. Work with your authentication platform vendor to see if they support 2-factor authentication when there is a high probability that account credentials have been shared. 
  • Be mindful if your support team troubleshoots customer issues by logging in using the subscriber’s username and password. If a support team member does this, the support team member’s profile will merge with the subscriber’s. Support teams should use Chrome Guest Mode or Incognito to test if they absolutely must log in using the subscriber’s credentials.

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