# Google Tag Manager Integration
You can integrate with Tracknow in order to be able to track sales on your website using Google Tag Manager.
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In this integration, GTM is used in order to load the necessary scripts.
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### Prerequisites
This integration method require you to enable passing our unique affiliate identifier `click_id` to your landing page.
For instructions, click [here](https://docs.tracknow.io/integrations/passing-click_id-to-a-landing-page).
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### Storing the `click_id` Using GTM
Once the click\_id is passed to the webstore, it should be saved in a browser cookie to ensure it persists as the customer navigates between pages. The `click_id` must still be available after a successful purchase so it can be included in the postback to Tracknow together with the purchase details.
In Google Tag Manager, create a new **Page View** trigger and set it to fire on **All Page Views**. This ensures the `click_id` is captured and saved no matter which page the customer lands on, so it won’t be missed if they enter the site on a deep link.
Finally, you’ll need to add the script responsible for storing the `click_id`.
In GTM, go to **Tags** → **New** → Create a **Custom HTML** type tag.
```javascript
```
Copy the code above, **replace the ENTER YOUR NAMESPACE HERE placeholder with your actual Tracknow namespace** and paste the adjusted code in the GTM custom HTML code box.
Select the trigger you previously created as this tag’s trigger.
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### Sending Purchase Data Using GTM
To send purchase data to Tracknow, use the webstore’s **Thank You / Order Confirmation** page as the trigger for firing the postback. This ensures the postback is sent only after the purchase has been successfully completed.
In GTM, create a new **Page View** trigger and set it to fire on **Some Page Views**. Then configure the condition so it fires only when the webstore’s **Thank You** page is viewed: set **Variable** to **Page URL**, choose **Contains** as the match type, and enter the Thank You page URL path (e.g., /thank-you).
Next, you’ll need to add the script responsible for storing sending the postback.
In GTM, go to **Tags** → **New** → Create a **Custom HTML** type tag.
```javascript
```
Copy the code above and update the placeholders as follows:
* Replace **ENTER CAMPAIGN ID HERE** with the **Tracknow campaign ID** you want to attribute the conversion to.
* Replace **ENTER NAMESPACE HERE** with your **Tracknow** **namespace**.
You can include additional parameters in the postback to capture more purchase details from the webstore by adding them under the script’s **params** object. To see the full list of parameters Tracknow supports, [click here](https://docs.tracknow.io/integrations/supported-parameters).
For any parameter that should be populated dynamically (for example, the order total or order ID), replace the placeholder value in the code with the correct **macro** (Data Layer Variable Name) for that value (as provided by your webstore/GTM setup).
Select the postback trigger you previously created as this tag’s trigger.
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### Important Notes
On single-page applications (SPAs), navigation typically happens without a full page reload. As a result, a standard **Page View** trigger may not fire when the user moves between routes. In these cases, use a **History Change** trigger to detect URL changes and fire your tag accordingly.
