# S2S Tracking (Server to Server)
# s2s (Server to Server) Tracking
### **Click code is an advanced tracking method.**
This is a server-side tracking method that does not require any client cookie information.
It works by passing back a **eucid** (encrypted user cookie id) value which is added to your landing page URL whenever the user clicks on any of your ads served through Eskimi DSP.
When the user completes a successful conversion event, the advertiser needs to transmit **eucid** value back to the Eskimi DSP server by calling back the DSP server's conversion tracking pixel.
Once the **eucid** is validated on a server, a successful conversion event will be recorded and will appear on the campaign performance optimisation tool.
**Eucid pass to the advertiser**
When the user clicks on one of your ads, Eskimi DSP adds a **eucid** (click code) parameter to the landing page URL and redirects the user to your landing page.
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### **Examples**
The example below shows how the landing page URL looks before and after user is redirected with added **custom\_name** parameter:
**before**: [http://advertisersite.com/campaign.php?custom\_name={eucid}](http://advertisersite.com/campaign.php?custom_name=%7Beucid%7D)
**after**: [http://advertisersite.com/campaign.php?custom\_name=MTAwMjZfNjU4NTg4NDFfbmdf](http://advertisersite.com/campaign.php?custom_name=MTAwMjZfNjU4NTg4NDFfbmdf)
The advertiser is allowed to use a custom parameter name instead of *eucid* by adding {eucid} macro to the landing page URL while setting up the new campaign. This will be replaced with a unique **eucid** value automatically.
**Importance of eucid transportation**
The advertiser is required to store the passed **eucid** until a successful conversion or end of the session occurs.
To perform a one-time conversion notification, the advertiser needs to issue the **eucid** by HTTP request from the server-side (s2s).
From the examples above, we already know that **eucid** value is MTAwMjZfNjU4NTg4NDFfbmdf. The advertiser is required to keep this value until a successful conversion occurs.
**Conversion tracking**
After a successful conversion event, the advertiser will need to pass the **eucid** value by making a server-side HTTP request (s2s) to the URL [https://dsp.eskimi.com/pixel?eucid=MTAwMjZfNjU4NTg4NDFfbmdf](https://dsp.eskimi.com/pixel?eucid=MTAwMjZfNjU4NTg4NDFfbmdf)
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### **Implementation**
To enable click code based conversion tracking, the advertiser needs to pass back the **eucid** parameter value to Eskimi DSP conversion pixel by requesting it by **s2s** (server to server) method.
- **Eskimi Postback URL for s2s tracking with redirect:**
Our Postback URL for s2s tracking: *[https://dsp.eskimi.com/pixel?eucid={random\_click\_id}](https://dsp.eskimi.com/pixel?eucid=random_click_id)*
This Postback URL has to be implemented on your server side.
*The random\_click\_id* needs to be replaced with your click\_id macro, so when conversion happens it should send the value for click id which delivered conversion.
- **Eskimi Postback URL for s2s tracking without redirect:**
This tracker can be used by advertisers which do not support redirect in postback request. This is unusual case because most of systems support redirect.
Our Postback URL for s2s tracking: [https://dsp-ap.eskimi.com/campaign/pixel?eucid={random\_click\_id} ](https://dsp-ap.eskimi.com/campaign/pixel?eucid=%7Brandom_click_id%7D)
*The random\_click\_id* needs to be replaced with your click\_id macro, so when conversion happens it should send the value for click id which delivered conversion.
**Available Eskimi parameters/macros for Postback URL(Which we can show to the customer if asked):**
[](https://manual.eskimi.com/uploads/images/gallery/2025-02/YGde14QIIz60ha6R-image-2.png)