What is a Supply Side Platform?

Ben Morrisroe
December 21, 2020

Advertisers are increasingly using DSPs and exchanges to purchase their online advertising, but what about publishers? What are supply-side platforms actually for? And why are SSPs commonly referred to as yield-optimization platforms?

Let’s take a closer look and find out.

What is a supply-side platform (SSP)?

A supply-side platform (SSP) is an advertising technology (AdTech) platform used to coordinate and manage the supply and distribution of ad inventories. SSPs help digital media owners and publishers sell digital ads in automated auctions.

The purpose of SSPs is to efficiently improve the yield optimization of advertising space inventory on websites and mobile apps to minimize wasted space and maximize views. In short, SSPs allow publishers to sell their inventory to the best ad network.

The SSPs of today are a key part of the real-time bidding process, as they enable publishers to optimize yield by simultaneously connecting their inventory to multiple ad exchanges and demand-side platforms (DSPs). By opening up impressions to as many potential buyers as possible, publishers can maximize the revenue they receive for their inventory. For this reason, SSPs are sometimes referred to as yield-optimization platforms.

Where do SSPs sit in the online advertising ecosystem?

SSPs play a key role in RTB media transactions. They connect to ad exchanges, ad networks, data management platforms (DMPs), and demand-side platforms, helping publishers manage the complexity of the programmatic ad-buying process.

There are a number of processes and requirements SSPs handle, including:

  1. Real-time bidding transactions. SSPs sell a publisher’s inventory to DSPs in an automated fashion via ad exchanges.
  2. Ad-network optimization. Since SSPs sell individual ad impressions, they provide publishers more control over their inventory. Publishers can see who is paying or their inventory on the impression level and optimize their ad requests accordingly.
  3. Frequency capping. SSPs and DSPs work together to run frequency capping, which is the process of recording the number of times a specific visitor is shown a particular advertisement and then limiting the number of times that visitor sees that ad.
  4. Relevancy. With an SSP, the publisher can make sure that only relevant ad networks are considered in the process.

What are the main components and features of an SSP?

Let’s take a closer look at the features and components that make up many of today’s SSPs.

Components of an SSP

  • Backend and infrastructure – carry out the technical processes that power the SSP’s ability to sell ad space.
  • Integrations – SSPs can integrate with other AdTech platforms to facilitate both the selling of inventory and maximization of profits.
  • Ad Exchange – most SSPs incorporate ad exchange functionalities, enabling publishers to connect directly to advertisers without having to connect to external ad exchanges.
  • Trackers – collect data about the publisher’s website and target audience.
  • Reporting database – receives data from the tracker, giving publishers greater transparency about campaign performance.

Features of an SSP

  • User interface – allows publishers to leverage the SSP to their advantage.
  • Analytics and reporting – enables publishers to get full transparency about the performance of their inventory, including fill rates, clicks and impressions.
  • Header bidding– most SSPs incorporate header bidding functionality, allowing publishers to obtain bids from multiple DSPs, and manage their header bidding wrappers and demand partners.
  • Yield optimization – aims to increase revenue for publishers by improving fill rates, setting floor prices, and managing auction mechanics.
  • Inventory and campaign management – allows publishers to manage different types of inventory and block certain types of ads.

How does a supply-side platform (SSP) work?

How does a supply side platform (SSP) work?

The functionality of these platforms has expanded over the years.

Traditionally, publishers manually assigned ads to spaces. However, due to the large audiences and rising number of digital marketers all competing for the same ad space, manual placement is no longer efficient.

Now, supply-side platforms work with similar technology and together with demand-side platforms (DSPs) to evaluate advertisers, take stock of publishers’ total inventory, set the bidding range, and then make recommendations for the best match for each space. SSPs allow publishers to filter ads by the advertiser and other criteria, as well as set different rates for ad spaces to define the cost.

The process takes place in multiple micro-transactions across the digital advertising supply chain. The supply-side platform can make the inventory available to buyers directly or via ad exchanges, demand-side platforms, and agencies.

How publishers use SSPs to sell their inventory during RTB

Here’s a brief overview of how publishers use supply-side platforms to sell their inventory during real-time bidding:

  1. SSPs send available ad impressions to as many potential buyers as possible. The main goal is to sell all the inventory at the best price.  
  2. The SSP automatically evaluates requirements matching the right bid with the right inventory, and finally sending a request to the ad server.
  3. It will hold the publisher’s inventory. Once agreed upon, the publisher will submit a webpage as the source for an ad.
  4. Once agreed upon, they will put a pixel code on their page to track visitor behavior. The code delivers anonymous data about visitors and the actions that they take. It is programmed to maximize the value that publishers receive from an impression of an ad.  

What is the difference between SSP and DSP?

The difference between supply side platforms (SSP) and demand side platforms (DSP)

 As mentioned above, the supply-side platform (SSP) is a technology platform used by publishers to connect their inventory to ad exchanges. An SSP allows publishers to filter ads by the advertiser and other criteria, as well as set different rates for ad spaces to define the cost.

DSP refers to the demand-side platform. It allows the buyers of digital ad inventories to manage multiple ad exchanges via one interface.

The buyers commonly include trading desks, agencies, or advertisers directly. The demand-side platform must plug into an SSP to enable the buyer to bid on digital inventory. To enable that the buyer can bid on digital inventory, the demand-side platform has to plug into an SSP.

Simply put, a DSP and an SSP connect to different parts of the programmatic ecosystem. A demand-side platform (DSP) is a tool used by advertisers to help organize ad-buying, whereas a supply-side platform is used by publishers to automate the sale of advertising space, which is the supply-side of the demand-side platform.

How do SSPs help publishers?

The supply-side platform will help open advertising inventory for bidding to multiple ad buyers on various ad exchanges and networks and demand-side platforms.

SSPs help you establish a connection with a larger number of advertisers and manage the complexity of working with multiple ad networks or ad exchanges at once.

Additionally, a good supply platform should be making your inventory available to a wide variety of buyers in the market for the maximum price.

Your daily goal would be to sell all your inventories for the highest price.

Working with a high-quality supply-side platform guarantees a win for your business because multiple high-quality demand sources ensure inventory is sold at the highest price.

For publishers, the main advantages of SSPs include:

  • Granular reporting

Reporting and data analysis is extremely important for a successful business to understand what is working well, and what is not.

To maximize your profits, you need to know how much you are earning from your inventory and its value.

A good platform will provide you with an in-depth reporting system. This will help you make the right decision for how best to sell your inventory or how to optimize your yield.

  • Dynamic price floor

An exceptional SSP should give you the ability to set soft and hard price floors at a minimum CPM. This flexibility will allow you to maximize your revenue.

  • Aggregation of multiple networks

SSPs can connect to multiple networks, ad exchanges, and DSPs, allowing more buyers to take part in the real-time bidding process and enabling you to achieve better yield.

  • Simple and transparent

The programmatic landscape is quite complex, although its purpose is to simplify the advertising process. A supply-side platform should be simple to use, easy to integrate and provide all data to analyze your performance.

Since SSPs can be set to only offer inventory to specific buyers or through certain channels, they can offer better brand safety by blocking unwanted ads from showing on your website.

What are the main SSP companies in the programmatic ecosystem?

SSPs are one of the leading players in the online advertising ecosystem and play a key role in real-time bidding (RTB) media transactions.

They connect to ad exchanges, ad networks, data-management platforms (DMPs) and demand-side platforms (DSPs) to sell ad inventory on behalf of publishers, such as websites and app owners.

Those platforms help publishers manage the complexity and volatility of the programmatic ad-buying process, especially when managing multiple ad networks and their diverse requirements and limitations.

There are many SSP companies. Choosing an SSP company might depend on the strategy, goals, budget, type of campaign and targeted audience. That said, finding the best one for your specific needs is extremely important to help your business succeed.

Below are some of the best companies currently offering SSP technology:

  • Google Ad Manager

Google Ad Manager (formerly DoubleClick for Publishers), is a comprehensive, Google-hosted ad serving platform that streamlines your ad management.

  • MoPub

MoPub is a Twitter company that provides monetization solutions for mobile app publishers and developers around the globe. They have a flexible network mediation solution, leading mobile programmatic exchange, and years of expertise in mobile app advertising. Publishers trust them to help maximize their ad revenue and control their user experience.

  • AppNexus Marketplace

AppNexus is an American multinational technology company operating a cloud-based software platform that aims to enable and optimize programmatic online advertising. They have an open, transparent marketplace and powerful enterprise technology that helps marketers connect and engage consumers on thousands of high-quality websites and apps.

The ads they buy fund award-winning journalism, music, video, and games – all at little or no cost to the consumers who enjoy open access to this premium content. AppNexus was acquired by AT&T in June 2018.

  • Wunderkind (formerly BounceX)

You can use Wunderkind to accurately recognize and market to the actual person behind every visit in real-time.

  • Rubicon

Rubicon’s automated advertising platform is used globally by leading applications and publishers to transact with major brands and reaches over one billion consumers.

  • PubMatic

The PubMatic platform empowers independent app developers and publishers to control and maximize their digital advertising businesses. It enables advertisers to drive ROI by reaching and engaging their target audiences in brand-safe, premium environments across ad formats and devices.

Publift works with almost all the above companies as well as others. By having many SSPs, your business will be able to get insights from all the platforms to get the best deal.

How to choose the best supply-side platform?

Throughout the years, Publift has worked with many different partners to test their performance and assess their value to publishers.

The SSPs that stood out to us as the most consistent performers were Google Ad Manager or AdX, Rubicon, & Pubmatic.

Several attributes define a good SSP. When it’s time to choose which to use, unless you are an expert, it is beneficial to see what the professionals say. Publift offers this service to you. However, it is helpful to have a basic knowledge of how it works.

Here are a few key attributes to check for when choosing the best SSP for your business:

  1. Easy integration. It must have an ad server designed for easy integration of new demand platforms. Because the demand often fluctuates and publishers get different offers from different ad networks and ad agencies, it’s essential to keep track of the changes. You want it to search for high-quality demand sources.
  2. Real-time. Use a platform that focuses on real-time statistics, which means using the granular and updated real-time figures.
  3. Simplicity. You don’t want to hire a new developer that takes care of checking and troubleshooting. The publisher should choose one that provides a simple implementation process. However, because it can be challenging to find simplicity in a high-tech environment, we suggest trusting a professional, such as Publift.
  4. Comprehensive. You need the option of adding header bidding that integrates with tags. For example, Publift uses Fuse. Fuse is an all-in-one programmatic advertising solution for publishers. It is powered by a single piece of code that brings together all the essential elements needed to maximize programmatic ad revenue on your site.


An excellent supply-side platform (SSP) for publishers should be working to keep bad ads off your site and give you the ability to make decisions about what advertisers are allowed or not allowed to do on your website. It also needs to have all the above-mentioned characteristics.

Are you able to find The Perfect SSP that ticks all the necessary boxes? Do you know which partner to trust?

Publift has the experience, knowledge, and connections you need to make your life easier. And, with an average 55% growth in net revenue in six months of using Fuse, we help our clients get proven results. Reach out to us so we can show you how.

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