---
title: "Customer profiles and identity explained | Snowplow Signals"
description: "Building a profile from behavior, and stitching anonymous visits to a known user."
source: https://signals.snowplow.io/learning/customer-profiles-and-identity
---

Learning Center

# Customer profiles and identity

A customer profile is what a system reads to know who it is dealing with. These explainers cover what a profile is, what fills it, how identity resolution links a customer across devices and sessions, and why a profile has to be current to be worth reading.

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## In this topic

[What is a customer profile?A customer profile is the single record of what you know about a customer, from identifiers and attributes to recent behavior. Systems read it to decide what to show or do next.](https://signals.snowplow.io/learning/customer-profiles-and-identity/what-is-a-customer-profile) [Behavioral vs declared customer dataDeclared data is what a customer states about themselves, like preferences set at signup. Behavioral data is what they actually do, captured as events. Declared data ages; behavioral data keeps a profile current.](https://signals.snowplow.io/learning/customer-profiles-and-identity/behavioral-vs-declared-customer-data) [What is identity resolution?Identity resolution is the process of linking the identifiers a customer uses across devices and sessions to a single customer. It turns scattered activity into one profile.](https://signals.snowplow.io/learning/customer-profiles-and-identity/what-is-identity-resolution) [What is an identity graph?An identity graph records the connections between the many identifiers a single customer uses. It is how a system answers whether two ids belong to the same customer.](https://signals.snowplow.io/learning/customer-profiles-and-identity/what-is-an-identity-graph) [Deterministic vs probabilistic identity matchingDeterministic matching joins identifiers on exact shared data, like the same login or email. Probabilistic matching infers a link from evidence like device and behavior. They trade precision for reach.](https://signals.snowplow.io/learning/customer-profiles-and-identity/deterministic-vs-probabilistic-identity-matching) [What is identity stitching?Identity stitching connects the activity a customer generated under one identifier, like an anonymous cookie or a second device, to the rest of their profile once the link is known. It keeps their whole history attached to one person.](https://signals.snowplow.io/learning/customer-profiles-and-identity/what-is-identity-stitching) [Why a customer profile needs to be real-timeA customer profile is only as useful as it is current. When a system reads a profile to decide what to do in the moment, data from yesterday describes a customer who has already changed.](https://signals.snowplow.io/learning/customer-profiles-and-identity/why-a-customer-profile-needs-to-be-real-time) 

## Start with the free tier 

Read the ideas, then put them to work: add the SDK, define one attribute, and see an attribute updating against your own traffic in the first session. The free tier runs on the real engine: no card, no sales call.

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