# OperaAds Cookie mapping Integration Guide

Cookie Mapping is a feature that enables you to map your cookie—for example, an ID for a user that browsed your ads—with a corresponding OperaAds User ID, and construct user lists that can help you make more effective bidding choices. This guide describes concepts used in Cookie Mapping, as well as Cookie Mapping workflow.

# Concepts

Bidders typically set the contents of cookies for users that browse their ads, which are used to identify users within that bidder. Even if two bidders would otherwise agree to exchanging this data, the security model of internet browsers restricts one from reading a cookie set by another domain.

In the context of digital advertising, OperaAds identifies users with cookies that belong to the adx.opera.com domain, and bidders participating in Real-Time Bidding may have their own domain where they identify some set of users they would like to show ads. Cookie Mapping enables the bidder to map their cookies with OperaAds', such that they can determine whether an impression sent in a bid request is associated with one of users being targeted, they will receive a bidder-specific User ID in the bid request.

The cookie mapping service described in this guide facilitates the creation and maintenance of the association between a bidder's cookie and the OperaAds User ID.

# Mapping Table

A mapping table can be used to map an ID or other data from one domain to another. OperaAds uses the Cookie Mapping Service to map the user's OperaAds User ID to bidder's cookie data, normally bidder-specific user id. Once a mapping has been established, in OperaAds' OpenRTB implementation, BidRequest.user.buyeruid will be set to bidder-specific user id.

# Getting Started

In order to get started with Cookie Mapping, you must contact your Account Manager, who can enable specific workflows and help you configure the cookie mapping url, like https://t.adx.opera.com/sync?vendor=<bidder_id>&uid=. bidder_id is allocated by OperaAds.

In order to initiate this flow, a bidder must place a map tag such that it renders in the user's browser when BidRequest.user.buyeruid sent by OperaAds is empty. The map tag must direct the user's browser to your Cookie Mapping URL. For example, with a Cookie Mapping URL configured as https://bidder.adnetwork.com/pixel, it would look like:

<img src="https://bidder.adnetwork.com/pixel" />

When loading in the user's browser, it will request a pixel from the bidder's Cookie Mapping URL. This request will contain their cookie in the HTTP header, which should be extracted for the next step.

The bidder's cookie mapping endpoint must redirect to OperaAds' Cookie Mapping service, including bidder-specific user id appended. The redirect URL might look like the following:

https://t.adx.opera.com/sync?vendor=600001&uid=4e93fa9e-86e3-11eb-8dcd-0242ac130003

OperaAds will receive a redirect containing the parameters you specified, in addition to OperaAds' cookie in the HTTP headers.

# Step 4: OperaAds serves pixel on the end

If the cookie mapping operation is done, OperaAds will serve a 1x1 transparent pixel by default, and the workflow will end here. Bid requests for this user will include bidder-specific user id as BidRequest.user.buyeruid for OperaAds' OpenRTB implementation.