Braze identity resolution guide: design reliable customer profiles across web, mobile, backend systems and engagement channels.

Define the identity hierarchy

Start with the business identity that should be stable across channels, then define how device IDs, anonymous states, external IDs and other identifiers relate to it. Document the authoritative key for every source before any profile merge or aliasing logic is introduced.

Implementation note: Avoid using email address alone as a universal technical identifier unless the business and security model explicitly requires it.

Handle anonymous-to-known transitions deliberately

Web and mobile experiences often collect behavior before login or signup. Define when and how that behavior becomes associated with a known profile, what happens to conflicting attributes, and how downstream journeys should behave after the transition.

Implementation note: Test the transition as a first-class customer state rather than treating it as a one-time data migration.

Protect data quality during merges

Profile stitching errors can create duplicate messaging, missing preferences or contaminated analytics. Add validation rules for identifiers, inspect duplicate rates and monitor unexpected attribute changes after identity operations.

Implementation note: Keep merge and identity rules small enough to explain to a campaign operator and an engineer using the same diagram.

Govern identity changes

Identity decisions affect every downstream capability: segmentation, preferences, personalization, exports and analytics. Assign an owner, version the mapping rules and include a rollback or reconciliation procedure for bad data.

Implementation note: When identity rules change, run a regression against representative customer profiles before scaling new campaigns.

Production scenario: app login transition

A customer browses anonymously, signs up, then logs in on a second device. The data architecture assigns the intended profile key, moves the relevant durable state into the known customer record, and rechecks subscription and journey eligibility. A duplicate-profile report verifies that the same customer is not being targeted twice.