# User Sync

Zotlo allows seamless transitions between **web** and **mobile app** experiences. Whether a user moves from **web → app** or **app → web**, Zotlo ensures that identity, payments, and subscription states stay perfectly synced.

## **Web → App** 

### **What is Web→App**

Web→App is the flow where a user starts on your **web sales site** and continues the journey inside your **mobile app**.

This commonly occurs after onboarding funnels, quizzes, long-form landings, or pricing pages where the **"Open in App"** or **"Install App"** CTA is displayed after successful payment.

You can explore the Zotlo [Quiz Funnels](https://docs.zotlo.com/features/quiz-funnels/funnels-flows-overview). 

### **When To Use**

Use Web→App when you want to:

* Convert mobile web visitors into app users
* Personalize the user journey before app install (quizzes, funnels, offer pages)
* Explain value before pushing users into the app
* Show localized or segmented offers based on country or behavior
* Capture UTM & attribution information **before** users move into the app

Ideal for **Facebook Ads, Google Ads, TikTok Ads, Snapchat, DSP campaigns**.

### **User Sync** 

When a user later installs/opens the app, Zotlo syncs all related data back into the app.

#### **How syncing happens**

* **Webhooks** → subscription, payment, registration, quiz response events
* **API services** → subscription status, payment history, customer info
* **Custom parameters** → subscriberId, session ID, attribution IDs (AF ID, GAID, IDFA, Adjust ID), language, country

#### **What gets synced**

* Active subscription state
* Renewals & cancellations
* Payment successes & failures
* Registration data
* Quiz answers
* Web purchases matched to the correct app user

### **Ads & Analytics**

Zotlo can forward events to advertising and analytics platforms with **100% web tracking accuracy**, including:

* Meta Ads (Pixel + CAPI)
* Google Ads (Purchase Events)
* TikTok Ads
* Google Analytics
* Google Tag Manager

This ensures Web→App conversions are correctly attributed.

### 🔗 **Useful Documents**

→ [Subscription Status Webhook](https://docs.zotlo.com/integrating-zotlo/webhooks/subscription-status-webhooks)\
→ [Payments Webhook](https://docs.zotlo.com/integrating-zotlo/webhooks/payments-webhook)\
→ [Users Webhook](https://docs.zotlo.com/integrating-zotlo/webhooks/user-registration-webhook)\
→ [Quiz Responses Webhook](https://docs.zotlo.com/integrating-zotlo/webhooks/quiz-responses-webhook)\
→ [3rd-party Integrations](https://docs.zotlo.com/3rd-party-integrations)

## **App → Web** 

### **What is App→Web**

App→Web is the flow where the user starts inside a **mobile app** and is redirected to a **secure Zotlo web checkout** to complete the purchase.\
This flow is fully compliant with updated **App Store & Google Play rules**, where applicable.

### **When to use**

Use App→Web when you want to:

* Offer payment methods beyond IAP (Card, PayPal, Apple Pay, Google Pay)
* Reduce or avoid app store commissions
* Use a more flexible checkout
* Keep subscription logic fully external to the app
* Redirect users back to your app after payment

Great for global subscription apps or apps that want to legally bypass store fees.

{% hint style="info" %}
**Legal Status**

* **iOS:** Legal in US, EU, South Korea, Netherlands (only dating apps), Japan (only reader apps)
* **Android:** Legal in all UCB-supported markets
  {% endhint %}

### **User Sync**

When redirecting to web checkout, apps can pass the necessary identifiers so the checkout immediately recognizes the user.

#### **Identifiers to pass**

* `subscriberId`
* Language & country
* Custom parameters (AF ID, Adjust ID, internal user ID, session token, campaign data)

#### **How syncing happens**

* **Checkout Web SDK** → send subscriber + custom parameters
* **Personalized Checkout Link API** → generate user-specific URLs
* **Webhooks** → real-time updates after payments
* **API** → verify subscription status from the app

#### **What gets synced back**

* New subscription activations
* Renewals
* Cancellations & grace transitions
* Payment failures
* Entitlements & app-side access rights
* Attribution events

### **Deep Link & Attribution**

After a web payment, Zotlo can send the user back into your app using:

* **Universal Links / Deep Links**
* **Attribution parameters** (AppsFlyer, Adjust, Meta, Google Ads)
* **Custom session identifiers**

This ensures purchases made outside the app are still attributed and applied correctly.

Zotlo also pushes successful web purchases to attribution platforms:\
→ [AppsFlyer Integration](https://docs.zotlo.com/3rd-party-integrations/attribution/appsflyer)\
→ [Adjust Integration](https://docs.zotlo.com/3rd-party-integrations/attribution/adjust)

### 🔗 **Useful Documents**

→ [Checkout Web SDK](https://docs.zotlo.com/integrating-zotlo/web-sdk/checkout-sdk)\
→ [Personalized Checkout Link API](https://docs.zotlo.com/integrating-zotlo/api-reference/checkout-endpoints)\
→ [Full API Reference](https://docs.zotlo.com/integrating-zotlo/api-reference/introduction)\
→ [Webhooks Services](https://docs.zotlo.com/integrating-zotlo/webhooks/webhooks-overview)