How to Set User Property in Firebase Analytics

To set a user property in Firebase, use the setUserProperties method on the Firebase Analytics instance, specifying the property name and value. This helps you track user attributes for better analysis and targeting.

Syntax

The setUserProperties method takes an object with key-value pairs where keys are property names and values are property values. The property names should be descriptive and follow Firebase naming rules.

• propertyName: The name of the user property (e.g., "favorite_food")
• propertyValue: The value to assign to the property (e.g., "pizza")

javascript

firebase.analytics().setUserProperties({ propertyName: 'propertyValue' });

Example

This example shows how to set a user property named favorite_color with the value blue using Firebase Analytics in a web app.

javascript

import { initializeApp } from 'firebase/app';
import { getAnalytics } from 'firebase/analytics';

const firebaseConfig = {
  apiKey: 'YOUR_API_KEY',
  authDomain: 'YOUR_AUTH_DOMAIN',
  projectId: 'YOUR_PROJECT_ID',
  appId: 'YOUR_APP_ID',
  measurementId: 'YOUR_MEASUREMENT_ID'
};

const app = initializeApp(firebaseConfig);
const analytics = getAnalytics(app);

// Set user property
analytics.setUserProperties({ favorite_color: 'blue' });

Output

User property 'favorite_color' set to 'blue' in Firebase Analytics.

Common Pitfalls

Common mistakes when setting user properties include:

• Using invalid property names (must be alphanumeric and underscores, max 24 characters)
• Setting property values longer than 36 characters
• Trying to set user properties before initializing Firebase Analytics
• Confusing setUserProperties with event parameters

Always initialize Firebase Analytics first and use valid names and values.

javascript

/* Wrong: property name with spaces and too long value */
analytics.setUserProperties({ 'favorite color': 'this value is way too long to be accepted by Firebase Analytics' });

/* Right: valid property name and short value */
analytics.setUserProperties({ favorite_color: 'blue' });

Quick Reference

Property	Description	Rules
propertyName	Name of the user property	Alphanumeric, underscores, max 24 chars
propertyValue	Value assigned to the property	String, max 36 chars, or null to clear
Initialization	Firebase Analytics must be initialized	Call getAnalytics(app) before setting properties
Usage	Set user properties to segment users	Use setUserProperties({ name: value })

Key Takeaways

Initialize Firebase Analytics before setting user properties.

Use valid property names with only letters, numbers, and underscores.

Keep property values short (max 36 characters).

Use setUserProperties method with an object of key-value pairs.

User properties help personalize and analyze user behavior.