Anonymous User Tracking and Pre-Login Identity Merging

The Tappd Web SDK tracks every visitor from their very first page view — even before they create an account or log in. Each anonymous visitor gets a stable identifier stored in their browser, and the moment they identify themselves, all of their previous activity is automatically merged into their user profile.

How Anonymous Tracking Works

First Visit — Anonymous ID Generated

When the SDK initializes for the first time, it generates a unique anonymousId (for example, anon_xyz789abc123) and stores it in localStorage under the key _tappd_anonymous_id. All events from this point forward are tracked against that ID.

const tappd = new TappdSDK({ appId: 'YOUR_APP_ID' });

// Anonymous ID is created automatically
const anonymousId = tappd.getAnonymousId();
console.log(anonymousId);
// Output: anon_abc123def456ghi789

Anonymous Events Are Captured

Every track() and trackPageView() call is recorded with the anonymousId. You don’t need to do anything special — it all happens behind the scenes.

// All of these are captured and attributed to the anonymousId
await tappd.track('page_view');
await tappd.track('button_click', { buttonId: 'cta' });
await tappd.track('add_to_cart', { productId: 'prod_123' });

User Identifies — Events Are Merged

When the user logs in or signs up, call identify(). The SDK automatically links all previous anonymous events to the newly identified user.

await tappd.identify({
  external_id: 'user_123',   // Required: your internal user ID
  email: 'john@example.com',
  name: 'John Doe'
});

// All previous anonymous events are now merged with user_123

Future Events Use the Identified User

After identify() is called, events are tracked with the identified user’s external_id. The anonymousId is retained as an alias for future matching.

Anonymous ID Persistence

The anonymous ID is designed to survive normal browser activity, but it resets when users explicitly clear their data.

Persists across...

Browser sessions
Tab refreshes
Browser restarts
Device reboots (same browser)

Resets when...

User clears browser data
User closes an incognito/private window
You call tappd.reset()

You can inspect the stored value directly:

// The anonymous ID is stored in localStorage
localStorage.getItem('_tappd_anonymous_id');
// Returns: anon_abc123def456...

Use Cases

E-commerce
SaaS

Capture product browsing and cart activity before a user creates an account, then attribute that behavior to the new user automatically.

// Anonymous user browses and adds to cart
await tappd.track('product_viewed', { productId: 'prod_123' });
await tappd.track('add_to_cart', { productId: 'prod_123' });

// User creates an account at checkout
await tappd.identify({
  external_id: 'user_123',
  email: 'john@example.com',
  name: 'John Doe'
});

// Cart and browsing history are now linked to user_123

Track pricing page visits and trial button clicks before signup so you can see the complete acquisition funnel from first touch to conversion.

// Anonymous user visits the pricing page
await tappd.track('page_view', { page: '/pricing' });
await tappd.track('button_click', { buttonId: 'start-trial' });

// User signs up for a trial
await tappd.identify({
  external_id: 'user_123',
  email: 'john@example.com'
});

// You can now see the full journey: pricing page → trial signup

Getting the Anonymous ID

const anonymousId = tappd.getAnonymousId();
console.log('Anonymous ID:', anonymousId);

Resetting Anonymous Tracking

Call tappd.reset() when a user logs out. This clears the current identity, regenerates a fresh anonymousId, and ensures the next user on the same browser starts with a clean slate.

function handleLogout() {
  tappd.reset();
  // A new anonymousId is generated automatically
  // The user is now anonymous again
}

Avoid calling reset() unless the user is explicitly logging out. Unnecessary resets break the anonymous-to-identified journey and prevent historical data from merging correctly.

Data Privacy

Anonymous tracking is built with privacy compliance in mind:

No personal information is stored in the anonymousId
Fully GDPR compliant
Users can opt out via standard browser privacy settings
Anonymous data can be deleted on request

Troubleshooting

Anonymous ID changes on every page load

Cause: The browser has localStorage disabled or blocked.Fix: Check for localStorage support before initializing the SDK:

if (typeof Storage !== 'undefined') {
  console.log('localStorage is supported — anonymous tracking will persist');
} else {
  console.log('localStorage is not supported — anonymous IDs will reset on each load');
}

Anonymous events are not appearing after identification

Cause: identify() was called without a valid external_id, or the anonymous context was lost before identification.Fix: Always pass a non-empty external_id when calling identify(). The SDK uses this to link the anonymous session to the user record server-side.

// Correct — SDK automatically includes the anonymousId internally
await tappd.identify({
  external_id: 'user_123',  // Required: must be a valid, non-empty string
  email: 'john@example.com'
});

Get Started

Core Features

Advanced

Reference

Anonymous User Tracking and Pre-Login Identity Merging

How Anonymous Tracking Works

Anonymous ID Persistence

Persists across...

Resets when...

Use Cases

Getting the Anonymous ID

Resetting Anonymous Tracking

Data Privacy

Troubleshooting

​How Anonymous Tracking Works

​Anonymous ID Persistence

Persists across...

Resets when...

​Use Cases

​Getting the Anonymous ID

​Resetting Anonymous Tracking

​Data Privacy

​Troubleshooting

How Anonymous Tracking Works

Anonymous ID Persistence

Use Cases

Getting the Anonymous ID

Resetting Anonymous Tracking

Data Privacy

Troubleshooting