Identity resolution is the process of determining that different customer identifiers, such as email addresses, phone numbers, and device IDs, belong to the same person, then consolidating that information into a single, unified profile. It’s the overarching framework that makes tools like an identity graph possible and powers mechanisms like identity stitching.
When someone engages with your brand through email, text messaging, mobile push, or your website, identity resolution connects those separate interactions to one person, giving you a more complete picture of who they are and how they behave.
This matters because your customers don't think about your brand in terms of channels or devices. They might subscribe to your emails on their laptop, sign up for text messages on their phone, and browse your site from a tablet. Without identity resolution, you might see 3 separate people instead of one. With it, you can deliver consistent, personalized experiences no matter where or how someone interacts with your brand.
How identity resolution works
Identity resolution relies on two core processes working together: identifying customers and resolving their profiles into a single record.
Identifying customers means recognizing who someone is based on information they provide at check-out or in sign-up forms, quizzes, or surveys, or digital signals you capture by observing someone’s behavior on your website and marketing channels.
Resolving profiles means consolidating those behaviors and identifiers into one unified view. This happens through one of two matching methods:
- Deterministic matching uses exact identifier matches, like the same email address and phone number appearing together at check-out. High confidence, no inference required.
- Probabilistic matching uses signals like device type, location, and behavioral patterns to infer that two records likely belong to the same person. Less certain than deterministic matching, but extends coverage to anonymous or partially-identified users.
For example, imagine one of your long-time email subscribers now subscribes to your SMS list by texting a keyword. This automatically creates a new customer profile associated with that phone number. But later, when this person makes a purchase and enters both their phone number and email at check-out, identity resolution recognizes that the phone-only SMS profile and the email profile belong to the same person, merging them into one complete record.
Key features of identity resolution
Effective identity resolution combines several capabilities to help you maintain accurate, unified customer profiles. Here are the core elements:
- Cross-channel tracking: captures customer activity across email, text messaging, mobile push, and your website, connecting interactions that happen on different devices or at different times
- Automatic profile merging: combines separate profiles into one record when they share a common identifier, like the same phone number or email address
- Anonymous activity backfill: tracks anonymous website visitors and links their browsing behavior to known profiles once they identify themselves through a form submission, email click, or check-out
- Cookie resilience: helps maintain tracking continuity even when browser cookies expire quickly, supporting the capture of more browsing events and relevant automations
Benefits of identity resolution
Identity resolution can support better customer experiences and more consistent data practices. Here are some ways it can help:
- More accurate customer data: clearer, consolidated records per person, helping reduce duplicate profiles and increasing confidence that your data reflects reality
- Smarter segmentation: customer segments built from unified profiles that reflect complete customer behavior across channels, not just one touchpoint
- Better personalization: ability to better tailor messages to someone’s full history, like what emails they’ve engaged with, which products they’ve browsed, and what they’ve purchased
- More effective automations: triggers and messages aligned to a fuller, more accurate view of browsing and purchase behavior, making experiences feel more timely and relevant
- Less redundant outreach: fewer duplicate sends across channels, reducing noise for customers and simplifying campaign management
Identity resolution brings fragmented customer data into a single source of truth, giving you a clearer picture of each customer and a stronger foundation for personalization.
Ready to unify your customer data across channels? Get started with Klaviyo today.