CTV Demand Integration for Publishers: VAST vs. OpenRTB

As CTV matures, publishers are redefining how they connect to programmatic demand. OpenRTB brings scalability and deeper control for those equipped with technical expertise, while VAST simplifies the path through established video ad servers. Choosing between them isn’t just a technical decision — it’s a strategic move that can shape the future of your CTV monetization.

Over the past decade, the Connected TV (CTV) market has experienced rapid growth in both audience size and advertising budgets, with programmatic advertising taking the lead.

According to the Internet Advertising Bureau (IAB US), CTV accounted for less than 1% of total digital programmatic ad spending in 2013. Ten years later, by 2023, its share had risen to 16.5%. Similar trends can be seen across other Tier-1 markets.

Audience interest in CTV applications continues to expand, driven by technological innovation, the rise of streaming platforms, and the growing popularity of gaming. Viewers are spending more time at home, watching their favorite shows and sports events, or playing games on large TV screens.

Publishers on Xbox and Sony PlayStation hold a distinct position in the CTV ecosystem — a topic we’ll explore in a future article.

Whether you’re new to CTV or an experienced publisher, one question remains crucial: How can you maximize your CTV app revenue while minimizing technical complexity?
The answer lies in building the right demand integration architecture.

As gaming becomes part of everyday life, reaching the right audience on the right screen is more crucial than ever. The fast growth of CTV publishers and SSPs shows how programmatic and gaming are merging into a unified ecosystem.

— Koray Fuat, Senior Supply Director, adWMG

The Two Primary Integration Methods

Today, many CTV publishers or supply partners connect their programmatic demand through one of two main approaches:

• OpenRTB Endpoint
• VAST (Video Ad Serving Template)

Each method offers specific technical requirements, benefits, and trade-offs. Let’s examine them in more detail.

OpenRTB Endpoint

An OpenRTB endpoint is a URL that receives backend requests and responds according to the IAB OpenRTB 2.5 or 2.6 specifications.

Integrating via OpenRTB requires a relatively complex technical setup — typically including an SDK, an Ad Exchange, or your own SSP (Supply-Side Platform). This model is commonly used by direct publishers or media agencies with qualified technical teams.

When integrating a demand partner, you’ll need to:

• Connect the DSP endpoint to your infrastructure.
   
• Configure all required parameters according to advertiser requirements (e.g., bundle ID, supply chain, COPPA, TCF, etc.).
   
• Agree on a unified impression-counting method.
   
• Regularly compare discrepancies between publisher and advertiser data for the same reporting period.
   

The main advantage of OpenRTB is scalability and flexibility. You can connect multiple demand partners, set a maximum response time (tmax) for each, and allow them to compete in real time for impressions.

That’s the core of Open Real-Time Bidding — the ad with the highest CPM wins the auction.

There are two primary auction models — First-Price and Second-Price — which will be covered in an upcoming article.

80% of your revenue will come from 20% of your partners. Focus on quality and work only with those who bring real value.

— Maksym Kovalenko, CEO, adWMG

VAST Integration

To deliver ad campaigns through VAST, publishers use a Video Ad Server.
In this model, you don’t necessarily need an in-house technical team. You can connect to leading CTV video servers such as Publica (by IAS) or SpringServe (now part of Magnite). Typically, one programmatic ad operations specialist manages the setup and optimization.

The main drawback of this method is the waterfall model.
Partner VAST tags are arranged in order of priority, and if a demand partner cannot return an ad (for example, due to a high CPM floor), the request moves to the next one. This process increases latency and limits the number of active partners.

However, there are ways to optimize performance. Modern VAST integrations are divided into:

• Client-Side VAST
   
• Server-Side VAST
   

If you choose Client-Side VAST, ensure your video player supports key SDKs — for instance, the PAL SDK or IMA SDK for Google demand.

With Server-Side VAST, publishers handle most parameters on their backend, reducing configuration errors and improving the likelihood that partner demand functions correctly.

Recommendations

If you’re a new CTV publisher with only a few applications:

• Start with VAST Client-Side.
   
• Connect to a trusted Video Ad Server such as Publica, SpringServe, or Google.
   
• Integrate PAL and IMA SDKs into your video player.
   
• Partner with five to seven reliable demand sources.
   
• Continuously adjust VAST priorities in your waterfall — prioritize the partners delivering higher CPMs.
   
• Keep your app-ads.txt file up to date.
   
• Monitor monetization efficiency yourself or assign a dedicated ad operations manager.
   

If you’re an experienced CTV studio:
This article may serve as a useful refresher — and if you need additional guidance, the professional team at adWMG is always ready to help.

Final Thoughts

The CTV ecosystem continues to evolve, offering publishers more effective ways to monetize content.
Understanding the differences between OpenRTB and VAST helps you choose the integration model that best fits your technical capabilities and business goals.

At adWMG, we believe that strategic integrations and reliable partnerships form the foundation for sustainable monetization success.

Your adWMG team.

Read more: adwmg.com