How can I find customer ID in custom pixels code?

Store Design

Topic summary

A developer needs to access the authenticated customer ID within Shopify’s custom pixels code for analytics tracking.

Initial Solutions Proposed:

  • Accessing window.ShopifyAnalytics.meta.page.customerId or similar global objects
  • Using Shopify Admin API with AJAX requests (requires access tokens and server-side authentication)
  • Storing customer ID in localStorage from theme.liquid using {{ customer.id }}

Working Solution:
The most reliable approach involves:

  1. Creating a custom event in the frontend that passes {{ customer.id }} from Liquid
  2. Publishing via Shopify.analytics.publish() with custom data
  3. Subscribing to the custom event in pixels code

Alternatively, accessing the init object within the pixel’s register function provides customer data: init.data.customer contains all logged-in customer information.

Remaining Issue:
One user reports that while customer data appears in the dataLayer object, it shows as undefined when attempting to send to third-party vendors like Google Analytics 4, suggesting potential restrictions on sharing customer data externally.

The discussion remains open regarding limitations on transmitting customer IDs to external platforms.

Summarized with AI on November 7. AI used: claude-sonnet-4-5-20250929.
1

Hello,

I need authenticated customer id in pixels code.

analytics.subscribe("product_added_to_cart", async (event) => {
  // I need customer id here
});

Do you know any way to get customer id?

Thanks

2

Hi @serkanersan ,

First , you add a custom function to find customerID

  var getCustomerId = function() {
    try {
      let curr = window.ShopifyAnalytics.meta.page.customerId;
      if (curr !== undefined && curr !== null && curr !== "") {
        return curr;
      }
    } catch(e) { }
    try {
      let curr = window.meta.page.customerId;
      if (curr !== undefined && curr !== null && curr !== "") {
        return curr;
      }
    } catch (e) { }    
    try {
      let curr = _st.cid;
      if (curr !== undefined && curr !== null && curr !== "") {
        return curr;
      }
    } catch (e) { }
    try {
      let curr = ShopifyAnalytics.lib.user().traits().uniqToken;
      if (curr !== undefined && curr !== null && curr !== "") {
        return curr;
      }
    } catch (e) { }
    return null;
  }

Step 2 : In your function , call it ,example

analytics.subscribe("product_added_to_cart", async (event) => {
  // I need customer id here
   let customerId = getCustomerId();
});

Good luck!

3

Hi @BSS-Commerce ,

Thanks for your answer.

I tried but it always return null.

4

Hi @serkanersan ,

As a developer, I apologize for the inconvenience you’ve encountered. However, due to Shopify’s security measures, direct access to customer information from the client-side using JavaScript can be restricted.

You can try it by using shopify API

First : You include Jquery in html file

After:

analytics.subscribe("product_added_to_cart", async (event) => {
  // I need customer id here
  $.ajax({
    url: "https://your-development-store.myshopify.com/admin/api/2023-04/users/current.json",
    method: 'GET',
    headers: {
      'X-Shopify-Access-Token': 'YOUR_ACCESS_TOKEN',
    },
    success: function(response) {
      if (response.customers.length > 0) {
        var customerId = response.customers[0].id;
      //  customer id here
        console.log("Customer ID:", customerId);
      } else {
        console.log("NoCustomer ID ");
      }
    },
    error: function(xhr, status, error) {
      console.log("error:", error);
    }
  });
});

Please note that querying customer information from the server-side requires proper access permissions and valid authentication. You need to provide the authentication details of your Shopify store and handle authentication securely within your server-side application.

Hope it’s useful to you @serkanersan !

5

Have you found any solutions?

  • I am currently thinking you can get the customer id on theme.liquid then save it to localStorage and get it from there.

you can get customer id with : {{ customer.id }}

1 Like
6

You can resolve this by creating a custom event.

In the frontend, publish the custom event as follows:

const customer_id = "{{ customer.id }}";
Shopify.analytics.publish("custom_product_add_to_cart", {product_id: "xxx", customer_id });

In this way, the custom event can send any data you want.

Next, subscribe to the custom event:

register(({analytics}) => {
  analytics.subscribe('custom_product_add_to_cart', (event) => {
    /*
      event = {
        id: "123",
        clientId: "2cabc5d8-e728-4359-9173-4b31265cbac0",
        name: "custom_product_add_to_cart",
        timestamp: "2011-10-05T14:48:00.000Z",
        context: { ... },
        customData: {
          product_id: "xxx",
          customer_id: "xxxx"
        }
      }
    */
  });
});

By doing this, you can obtain the customer ID using Web Pixel.

7

Hi @serkanersan , thank you for posting here!

You can follow my instruction below:

In the register function, you can access the .init object, then you can access all of the customer’s information once they have logged in.

register(({ analytics, browser, init, settings }) => {
  analytics.subscribe('product_added_to_cart', event => {
    console.log('product_added_to_cart', event);
    console.log('Customer', init.data.customer);
  });
});

console.log('Customer', init.data.customer);

If my answer is working for your store, please let me know by accepting Solution and giving Like !!!

2 Likes
8

Hi! Do you know if this field is restricted for sending to 3rd party vendors? Like GA4. All I’ve got is undefined, despite seeing it properly in the dataLayer(); object.