Fides Documentation – Ethyca

Identities

When Fides stores a user's consent records, it needs to know who those preferences belong to. An identity is the piece of information that connects a person to their consent choices -- it's what allows Fides to associate a set of preferences with a specific individual and retrieve them later.

What is an identity? Permalink for this section

An identity is any piece of identifying information your organization uses to recognize a person.

Built-in identity types Permalink for this section

Fides comes with the following identity types registered out of the box:

Identity type	Key	Description
Email address	`email`	A user's email address
Phone number	`phone_number`	A user's phone number
Fides user device ID	`fides_user_device_id`	A device-level identifier assigned by FidesJS

These built-in types are ready to use immediately -- you don't need to register them before saving or querying preferences.

Custom identity types Permalink for this section

Fides doesn't restrict you to the built-in types. You can register additional identity types that make sense for your organization, such as loyalty IDs, account numbers, or external system identifiers. Once registered, custom identity types work exactly like the built-in ones.

When registering a custom identity, you specify its data type using the type field:

Type	Description
`string`	A freeform string value (e.g., a loyalty ID, account number, or username)
`uuid`	A UUID string
`integer`	A numeric integer identifier
`email`	An email address
`phone_number`	A phone number

How identities are used Permalink for this section

When a user submits their consent choices, the submission includes both the preferences and the identity that those preferences belong to. For example, a consent submission might say: "The person identified by email: user@example.com has opted out of the 'Targeted advertising' notice."

Later, when you need to check what a person has consented to, you look up their preferences using the same identity type -- for example, by looking up all preferences associated with a specific email address.

Registering identities with Fides Permalink for this section

Before you can use a custom identity type to store or retrieve privacy preferences, you need to register it with Fides. This process is called creating an identity definition.

Why register identities? Permalink for this section

Registering identity types tells Fides which identifiers your organization uses and enables you to:

Store preferences by identity: When saving consent choices, Fides validates that the identity type you're using has been registered.
Look up preferences by identity: Registered identities become available as filters when retrieving preferences, so you can query preferences by email, phone number, loyalty ID, or any other registered type.
Keep your API discoverable: Registered identity types appear in the API schema, making it clear to developers which identity filters are available.

Example: registering a loyalty ID Permalink for this section

Suppose your organization identifies customers by a loyalty program number. To use loyalty_id as an identity for privacy preferences:

Register loyalty_id as an identity definition in Fides.
When saving a customer's consent preferences, include loyalty_id as the identity.
When retrieving a customer's preferences, filter by loyalty_id to find their consent choices.

Once registered, loyalty_id works just like the built-in identity types -- you can save preferences against it, query current preferences by it, and filter preference records with it.

[Consent Records](/content/docs/consent/concepts/fundamentals/consent-records "Consent Records"/index.html) [Consent vs Preferences](/content/docs/consent/concepts/fundamentals/consent-vs-preferences "Consent vs Preferences"/index.html)