User Identification

Link anonymous devices to logged-in users.

Overview

Identity management is critical for accurate funnels and retention analysis. The JS SDK automatically tracks anonymous users using a distinct_id stored in localStorage. When a user logs into your app, you must link their anonymous ID to their permanent database ID.

1. Identify (Login)

Call identify() immediately after a user successfully logs into your application.

EmpMix.identify('db_user_89012');

Parameter	Type	Required	Description
userId	string	Yes	The permanent, unique ID for this user in your database.
profile	object	No	Optional properties to immediately set on the user's profile in the database (e.g., name, email).

2. Alias (Sign Up)

The alias() method is used exactly once per user: at the exact moment they create an account. It tells the backend to link their past anonymous activity to their new permanent ID.

⚠️

Alias vs Identify

Use alias() only during the sign-up event. Use identify() for all subsequent logins.

// User fills out registration form and hits submit
const newUserId = response.data.id; // e.g., 'usr_abc123'

// 1. Alias the current anonymous ID to the new user ID
EmpMix.alias(newUserId);

// 2. Identify as the new user going forward
EmpMix.identify(newUserId);

// 3. Track the signup event (this will be attached to the new ID)
EmpMix.track('Signed Up');

3. Reset (Logout)

When a user logs out, you must clear their session data. Otherwise, subsequent events triggered by a different user on the same shared computer will be attributed to the logged-out user.

// Call this when the user clicks 'Logout'
EmpMix.reset();

reset() clears all Emp-Mix cookies and localStorage, generating a brand new anonymous distinct_id for the next session.

User Profiles (People API)

You can update a user's profile metadata without firing a specific event.

// Update or set properties
EmpMix.setUserProperties({
  last_login_date: new Date().toISOString(),
  plan: 'Pro'
});

// Increment numeric properties
EmpMix.increment('logins_count', 1);