September 27, 2023 | Expert Insights

A fusion of acronyms: RTB x DOOH

Everything you need to know about Real-Time Bidding in DOOH

Everything you need to know about Real-Time Bidding in DOOH

Real-time bidding (RTB) is an efficient marketplace whereby the buying and selling of impression-based advertising happens in real time through an automated auction process. It is a type of programmatic advertising where ad impressions are sold to the highest bidder in a matter of milliseconds. In the out of home (OOH) channel, RTB is applied via programmatic DOOH and was first introduced in September 2017 in Germany. Since then it has since been a driver of both investment and meaningful change for our industry. 

This process is usually facilitated across a Supply Side Platform (SSP) or an Ad Exchange, and a Demand Side Platform (DSP), much like in digital display and other programmatic channels. The Hivestack SSP and Ad Exchange enables publishers to sell impression-based DOOH inventory to potential buyers in real time via a unified auction. Buyers can come from various sources, including DOOH DSPs and the world’s largest omnichannel DSPs, giving publishers greater exposure to the world’s most influential brands. 

The process:

  1. A screen emits a bid request for an ad opportunity on either a deal or for an Open Exchange buy

  2. The SSP sends bid requests to potential buyers through its DSP integrations 

  3. The DSP receives the bid request, evaluates it based on the buyer's campaign strategy and targeting criteria, and decides to bid on it at an optimal price point

  4. Within this process, there is an additional layer of arbitration that takes place in the Ad Exchange

  5. The SSP or Ad Exchange analyzes all the bids received from DSPs and selects the highest bidder. This entire process happens in real time, typically within a few milliseconds

  6. The winning buyer's ad is served and displayed on the screen

RTB allows advertisers to target their ads to specific audiences based on factors like demographics, location, interests, and behavior. It also allows for more efficient and effective advertising, as advertisers can bid on only the ad impressions they want and only pay when their ad is shown to the right audience on the right screen at the right time.

Benefits of RTB

RTB empowers advertisers with the ability to reach their target audience more efficiently and effectively, by using data and insights to tailor their bids with behavioral, location-based, and contextual data. For media owners, RTB-based auctions enable them to get the best price (CPM) for their screen inventory whilst remaining in the driver’s seat of how their inventory is priced, what creative is approved to run and any additional data parameters to be set. Most importantly, it saves precious time and hassle, letting us all get back to what matters most. 


Programmatic digital out-of-home (DOOH) advertising refers to the automated buying and selling of digital out of home advertising space in real-time. Until recently, OOH has been largely transacted in a traditional insertion order (IO) manner which is largely manual and time consuming. RTB and programmatic technology has made several advancements to this process, not to replace traditional OOH but to coexist and support diversified ways to drive growth of the channel. It uses data and algorithms to make decisions about which ad to show, to whom, and at what time, facilitated by an auction-like sales process. Most notably, it has changed how DOOH is measured and sold, shifting to an impression-based model. 

Here's a brief overview of how programmatic DOOH + RTB works:

  1. Data selection: First, data from various sources, such as location-based data, audience demographic data, weather data etc. is selected by the buyer based on the campaign objectives. This data can be used to create a profile of the target audience and determine the most appropriate time and place to show the ad.

  2. Inventory selection: The buyer then selects the “total limit” or “maximum universe” of screens they want to run on. 

  3. Real-time bidding: Once the inventory is selected, the DSP places a bid on behalf of the advertiser to win the auction for ad space on the selected DOOH screen. 

  4. Ad serving: Now, the ad tech platform (in this case, the DSP) will rank the screens from step 2 based on the criteria from step 1; this ranking will then decide how much the platform wants to bid on the screen/opportunity. Once the bid is accepted, the ad is served to the selected screen  in real-time.

  5. Optimization and reporting: Programmatic DOOH advertising enables real-time optimization of ad campaigns based on performance data, such as impressions, clicks, and conversions. Advertisers can track their ad performance and adjust their campaigns accordingly.

Here is a high-level (simplified)  diagram that illustrates the process:


Ad Exchange: An Ad Exchange is a technology platform that facilitates the buying and selling of media advertising inventory from multiple ad networks

Ad impression: The ad exchange selects the highest bidder and sends the ad creative to the DOOH screen to be served - an ad impression is an ad play

DSP:  A technology platform that provides centralized and aggregated media buying from multiple sources including ad exchanges, ad networks and sell side platforms, often leveraging real time bidding capabilities of these sources

DMP: A data management platform (DMP) collects, organizes, and activates first-, second-, and third-party audience data from various online, offline, and mobile sources

Bid request: The digital out-of-home (DOOH) screen sends a request to the ad exchange, indicating that it has an available ad slot to sell. Advertisers who are interested in bidding on the ad slot receive the bid request via their DSP of choice

Bid Response: Via its DSP, the buyer then submits a corresponding bid response for the ad slot

Reporting: Both the DSP and SSP collects data on the ad impression and provides reporting to the user.

As we have seen, RTB directly benefits from how close DSPs and SSPs are integrated. The benefits for the ecosystem are vast and this buying process still has all of the transparency and accuracy that you'd expect from any advertising channel.

Overall, programmatic DOOH advertising allows advertisers to reach their target audience with highly targeted and personalized ads, while also optimizing their ad campaigns in real-time. RTB is a critical component of the process and has allowed for us to seamlessly navigate the end-to-end sales process in a matter of milliseconds. Talk about efficiency!