> For the complete documentation index, see [llms.txt](https://help.adgebra.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.adgebra.co/getting-started/publish-your-docs-10/win-notifications-and-user-syncing.md).

# Win Notifications & User Syncing

The platform supports two OpenRTB implementations:

1\. OpenRTB without “nurl” (default). In this scenario, “nurl” field is absent in bid responses and the system will record wins

automatically when impression happens. SSP has to replace ${AUCTION\_PRICE} before the ad markup is being rendered.

2\. OpenRTB with “nurl”. Win URL is represented as a separate bid response field. In case of 2nd price auction usage, “nurl” has

to be called before the actual impression happens.

**SSP Initiated User Matching**

\
To sync a particular user with AdKernel, the SSP should initiate the user to call for image or iframe pixel using the following URLs:

\
Image: \<img src='//sync.adkernel.com/user-sync?zone={zone\_id}\&t=image\&r=SSP\_REDIR\_URL' style ='display:none' width='0' height='0'>\</img>

Iframe: \<iframe src='//sync.adkernel.com/user-sync?zone={zone\_id}\&r=SSP\_REDIR\_URL' style ='display:none' width='0' height='0' frameborder='0'>\</iframe>

Where:

\- SSP\_REDIR\_URL is URL-encoded redirect URL to SSP that shall include macro {UID} which will be replaced with buyer’s userId;

\- {zone\_id} - SSP-specific zone id.

After performing successful user sync, SSP needs to sent DSP’s user id in user.buyeruid bid request field.<br>