OpenX Ad Server

Last updated January 16, 2019

OpenX Ad ServerA complete digital advertising platform where publishers sell, manage, and deliver their advertising inventory across all digital formats. is a platform that serves ads to your direct-sold inventoryAd space available on a website or app. The basic unit of inventory for OpenX is an ad unit.. It helps you channel sales of your advertising inventory using various online and mobile formats. By using targeting to match impressions with ads, Ad Server helps you increase revenue as a publisherAn account type that represents a business with ad space to sell.. With OpenX Ad Server, you can manage your inventory, review forecasts, traffic ads and run reports to track your progress, and more.

The following diagram shows the structure of basic OpenX Ad Server elements.

The following sections provide an overview of each element in the diagram.


An account represents a business unitA logical grouping of traffic sets in a Demand Partner's account. or business relationship and can be one of four types: ad networkAn OpenX account type, which represents a business that manages other businesses and typically contains and manages both publisher accounts and advertiser accounts., publisher, advertiser, or ad agencyIn OpenX, an account type that represents a business that provides services to advertisers.. You can create as many accounts as you need, at any level. An account contains objects, such as orders and line items, but the types of objects that it contains depend on the type of account.

Some ad tech platforms have flat structures, grouping ad units under other ad units; however, that kind of grouping is not allowed in OpenX Ad Server. The structure of OpenX Ad Server platform is hierarchical, and this structure enables you to group ad units by siteAn OpenX component that represents top-level domains or subdomains and is used to organize ad units. Sites enable you to target and report on inventory performance., ad unit groupA collection of ad units where related ads display together at the same time., or site sectionA way of classifying inventory, for example into vertical segments of content.. An ad unitThe smallest inventory component that represents the space on a site where ads display. group, for example, allows you to have competitive exclusion and targeting. Read more to find out how accounts can help you stay organized and efficient.

For details on account types and user roles, see Accounts and users.


Sites are a way of grouping ad units for targeting and reporting and are not inventory themselves. Sites live under publisher accounts, and you can define as many sites as you want; however, creating more than 500 sites can affect the performance of the OpenX product you are using.

Sites contain ad units. For OpenX, a site is a way to organize your ad units. Grouping your ad units by site makes it easier to find them, target ads, and report on your inventory performance. Sites can only be created under publisher accounts.

Ad units

An ad unit is the specific place on your site where you want to display an ad. Create an ad unit for every location on your site where an ad should be served. You can see ad units in at the bottom of the diagram below.

Each standard ad unit is a certain size, measured in pixels. A 728 x 90 ad unit is 728 pixels wide and 90 pixels high. OpenX also supports flexible ad units. Flexible ad units accept creatives of more than one size.

Each ad unit has a unique identifier and belongs to a single site.

When you create an ad unit in OpenX, you will receive an ad tagA small piece of code that defines the ad space where ads display on a website. It includes parameters that describe the inventory advertising campaigns can target, which may in turn display ads in the ad space., a piece of code to put in your website's source code. When a viewer loads the page, the ad tag communicates to OpenX and requests an ad that fits in the space allotted to it. This request is called an ad call. OpenX then finds an eligible ad and sends it to the ad tag. The ad tag puts the ad in the ad unit, and the viewer sees the ad.

For more detailed information on how a specific ad is selected, see Ad selection.

There are various inventory types for your ad units.


Orders are the first of three objects that must be set up for your advertiser account to display ads; the other two are line items and ads.

An order is a group of similar line items. To create line items, you must first create an order. The attributes you set at the order level will be the default settings for the line items in that order.

Line items

A line itemThe primary unit of execution for an order, which represents a specific inventory purchase and the required conditions for ad delivery. is a collection of similar ads created under an order in your Advertiser account. In the diagram below, you can see how line items relate to other objects.

At the line item level, you can decide settings like:

Note: Other ad tech platforms may enable you to set ad sizes on the line item level; however, the ad size setting for OpenX Ad Server is at the ad level.

Before you commit to serving a line item, you can also use the Forecasting tool to see a forecast of impressions that would be filled by the proposed line item, as well as revenue impact.


As shown int eh diagram above, underneath line items are ads. Ads contain creatives. Creatives are the media assets created for use in an ad, whether image, video, native, or HTML. Ads can be associated with one or more creatives.

At the ad level, you upload creatives and apply settings. An ad contains information about its creatives, like size, click target window, and landing page URL. The ad's information determines how its creatives are served and what happens when someone clicks them.

Note: OpenX Ad Server enables you to set the ad size at the ad level, but other ad tech platforms may house this setting elsewhere, like at the line item level.

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