Attributes

Attributes are the properties you target against in segments and targeting rules. When you build a condition like “country equals DE” or “plan is in [premium, growth]”, country and plan are attributes. Flagmint comes with built-in system attributes and lets you create custom attributes to match your application’s data model.

How Attributes Work

Attributes define what’s available in the attribute picker when you create targeting rules or segment conditions. Each attribute specifies its key, data type, allowed operators, and optional suggested values — so the dashboard knows how to render the right input fields and operator dropdowns.

Attribute picker dropdown showing user attributes like Country, Subscription Plan, Age, and Email with a search field and Create new attribute option

When the SDK sends an evaluation context, the evaluator matches context values against the attribute keys defined in your targeting rules. Attributes themselves don’t store user data — they’re a schema that tells Flagmint what properties exist and how to compare them.

Category	Prefix	Description
User	`user.`	Properties of the individual user (e.g. email, plan, role)
Organization	`organization.`	Properties of the user’s organization (e.g. country, employee count)
Device	`device.`	Properties of the user’s device or client (e.g. platform, browser)
Custom	`custom.`	Application-specific properties you define

System vs Custom Attributes

Flagmint ships with built-in system attributes covering common targeting scenarios (country, email, plan, age, etc.). These cannot be deleted, but they can be deactivated if you don’t need them — deactivated attributes are hidden from the attribute picker. Custom attributes are ones you create to match your specific application data. Custom attributes must use the custom category or have a key prefixed with custom..

	System Attributes	Custom Attributes
Created by	Flagmint (built-in)	You
Editable	No	Yes (label, operators, suggestions, description)
Deletable	No (can deactivate)	Yes
Category	Any	Must be `custom` or use `custom.` key prefix

Creating a Custom Attribute

From the Dashboard

Click + Create new attribute at the bottom of the attribute picker, or navigate to the attributes management page.

Fill in the details:

Key — Unique identifier used in targeting rules and the evaluation context. Must be lowercase, alphanumeric with dots and underscores only (2–255 characters). Examples: custom.tier, custom.signup_source, user.role.
Label — Human-readable name shown in the dashboard (e.g. “User Role”, “Company Size”).
Type — Data type of the attribute: string, number, or boolean. This determines which operators are available.
Category — Which context category this attribute belongs to: Custom, User, Organization, or Device.
Description (optional) — Explains what the attribute represents.
Suggestions (optional) — Comma-separated values shown as autocomplete suggestions in dropdowns (e.g. “admin, user, guest”).
Placeholder (optional) — Hint text shown in input fields when building conditions.

Via the API

curl -X POST https://api.flagmint.com/api/attributes \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "key": "custom.signup_source",
    "label": "Signup Source",
    "type": "string",
    "category": "custom",
    "operators": ["eq", "neq", "in", "nin", "exists", "not_exists"],
    "suggestions": ["organic", "referral", "paid_ad", "social"],
    "placeholder": "e.g., organic",
    "description": "How the user discovered the product"
  }'

Attribute Properties

Property	Type	Required	Description
`key`	string	Yes	Unique identifier. Lowercase, alphanumeric, dots, underscores. 2–255 chars.
`label`	string	Yes	Human-readable name shown in the UI
`type`	enum	Yes	`string`, `number`, or `boolean`
`category`	enum	Yes	`user`, `organization`, `device`, or `custom`
`operators`	string[]	Yes	Allowed comparison operators for this attribute
`suggestions`	array	No	Pre-defined values shown as autocomplete options
`placeholder`	string	No	Hint text for input fields
`description`	string	No	What the attribute represents
`is_custom`	boolean	—	`true` for custom attributes, `false` for system attributes
`is_active`	boolean	—	Whether the attribute appears in the attribute picker

Operators

When creating an attribute, you specify which operators are valid for it. The available operators are:

Operator	Description	Typical Types
`eq`	Equals	string, number, boolean
`neq`	Not equals	string, number, boolean
`in`	Is in list	string, number
`nin`	Not in list	string, number
`gt`	Greater than	number
`lt`	Less than	number
`exists`	Attribute is present	any
`not_exists`	Attribute is absent	any

The dashboard automatically shows the appropriate operators based on the attribute’s type. For example, a string attribute might allow eq, neq, in, nin, exists, not_exists, while a number attribute would also include gt and lt.

The operators defined on the attribute control what’s available in the dashboard’s condition builder. The server-side evaluator additionally supports contains, not_contains, startsWith, and endsWith — these can be used via the API even if not listed on the attribute’s operator set.

Managing Attributes

Updating a custom attribute

Only custom attributes can be updated. You can change the label, operators, suggestions, placeholder, and description. The key, type, and category cannot be changed after creation.

curl -X PATCH https://api.flagmint.com/api/attributes/custom.signup_source \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "label": "Acquisition Channel",
    "suggestions": ["organic", "referral", "paid_ad", "social", "email_campaign"]
  }'

Deactivating an attribute

Both system and custom attributes can be deactivated. Deactivated attributes are hidden from the attribute picker in the dashboard but remain in the database. Existing targeting rules that reference a deactivated attribute continue to work.

curl -X PATCH https://api.flagmint.com/api/attributes/device.browser/deactivate \
  -H "Authorization: Bearer YOUR_API_KEY"

Deleting a custom attribute

Only custom attributes can be deleted. System attributes return a 403 Forbidden error if you attempt to delete them. Deletion is permanent (hard delete, not soft delete).

curl -X DELETE https://api.flagmint.com/api/attributes/custom.signup_source \
  -H "Authorization: Bearer YOUR_API_KEY"

Deleting an attribute does not automatically remove it from existing targeting rules or segments that reference it. Those conditions will continue to evaluate but may behave unexpectedly if the attribute is no longer sent in the evaluation context.

Permissions

All attribute operations require authentication. There are no role-specific restrictions beyond being authenticated — any authenticated user can view, create, update, and delete custom attributes.

API Reference

Method	Endpoint	Description
`GET`	`/api/attributes`	List all attributes (paginated, filterable)
`GET`	`/api/attributes/{key}`	Get a single attribute by key
`POST`	`/api/attributes`	Create a custom attribute
`PATCH`	`/api/attributes/{key}`	Update a custom attribute
`DELETE`	`/api/attributes/{key}`	Delete a custom attribute
`PATCH`	`/api/attributes/{key}/deactivate`	Deactivate an attribute

The list endpoint supports filtering by category, is_active, and search (matches key or label), with pagination via page and limit.

Examples

String attribute with suggestions

{
  "key": "custom.tier",
  "label": "Customer Tier",
  "type": "string",
  "category": "custom",
  "operators": ["eq", "neq", "in", "nin", "exists", "not_exists"],
  "suggestions": ["free", "starter", "pro", "enterprise"],
  "placeholder": "Select a tier",
  "description": "The customer's subscription tier"
}

Numeric attribute for thresholds

{
  "key": "custom.monthly_spend",
  "label": "Monthly Spend (EUR)",
  "type": "number",
  "category": "custom",
  "operators": ["eq", "neq", "gt", "lt", "exists", "not_exists"],
  "placeholder": "e.g., 500",
  "description": "Customer's average monthly spend in EUR"
}

Boolean attribute

{
  "key": "custom.has_completed_onboarding",
  "label": "Completed Onboarding",
  "type": "boolean",
  "category": "custom",
  "operators": ["eq", "exists", "not_exists"],
  "description": "Whether the user has completed the onboarding flow"
}

Documentation Index

​Attributes

​How Attributes Work

​Categories

​System vs Custom Attributes

​Creating a Custom Attribute

​From the Dashboard

​Via the API

​Attribute Properties

​Operators

​Managing Attributes

​Updating a custom attribute

​Deactivating an attribute

​Deleting a custom attribute

​Permissions

​API Reference

​Examples

​String attribute with suggestions

​Numeric attribute for thresholds

​Boolean attribute

Attributes

How Attributes Work

Categories

System vs Custom Attributes

Creating a Custom Attribute

From the Dashboard

Via the API

Attribute Properties

Operators

Managing Attributes

Updating a custom attribute

Deactivating an attribute

Deleting a custom attribute

Permissions

API Reference

Examples

String attribute with suggestions

Numeric attribute for thresholds

Boolean attribute