What are Supply-Side Platforms (SSPs)

January 19, 2024

Supply-side platforms (SSPs), also known as sell-side platforms, are AdTech platforms that facilitate the management and distribution of ad inventories. They serve as acrucial component of programmatic advertising, specifically real-time bidding(RTB), enabling digital media owners and publishers to optimise their ad space selling process.

The Role of SSPs in Ad Selling SSPs play a vital role in the RTB process and handle various tasks and functionalities, including:

·       Real-time bidding transactions: SSPs automate the sale of a publisher's ad space to demand-side platforms (DSPs)through ad exchanges.

·       Ad-network optimisation: By selling individual ad impressions, SSPs offer publishers greater control over their inventory. Publishers can monitor who is bidding on their inventory at the impression level and optimise their ad requests accordingly.

·       Frequency capping: SSPs and DSPs collaborate to implement frequency capping, which limits the number of times a specific visitor is exposed to a particular advertisement.

·       Relevancy: With SSPs, publishers can ensure that only relevant ad networks are considered for their available ad space.

Key features of SSPs

SSPs offer several essential features that aid publishers in their ad selling process:

·       User interface: SSPs provide publishers with a user-friendly interface to effectively sell their impressions.

·       Analytics and reporting: Publishers can gain insights into the performance of their ad inventory, including metrics such as fill rates, clicks, and impressions, through comprehensive analytics andreporting tools.

·       Header bidding: Most SSPs incorporate header bidding functionality, allowing publishers to obtain bids from multiple DSPs and manage header bidding wrappers and demand partners.

·       Yield optimisation: SSPs aim to increase revenue for publishers by optimising fill rates, setting floor prices, and managing auction mechanics.

·       Inventory and campaign management: SSPs enable publishers to efficiently manage various types of ad inventory and block specific types of ads.

Understanding how SSPs work

In traditional advertising, publishers relied on human sales teams to manually assign ads to spaces. However, with the advent of programmatic advertising and the increasing competition for ad space, this manual approach became inefficient. SSPs leverage programmatic advertising technology to automate the evaluation of advertisers, to assess publishers' inventory, bidding range determination, and recommendation the best match for each space. Publishers can filter digital ads based on advertisers, target audience, ad format, and other criteria, whilst also setting rates for ad spaces.

The process involves multiple micro-transactions across the digital advertising supply chain. SSPs make the inventory available to buyers through ad exchanges, DSPs, and agencies. A pixel code is placed on the publisher's page to track audience data and behaviour, optimising the value derived from ad impressions.

Differentiating Supply Side Platforms and Demand Side Platforms

SSPs and DSPs serve distinct roles within the programmatic advertising ecosystem:

·       SSPs: These platforms connect publishers' inventory to ad exchanges, allowing publishers to filter ads, set rates, and optimise their yield. SSPs primarily serve the supply side of the market.

·       DSPs: Demand-side platforms enable buyers(advertisers, agencies, trading desks) to manage multiple ad exchanges through a single interface. DSPs facilitate the purchasing of digital ad inventory andfocus on the demand side of the market.

How SSPs Benefit Publishers SSPs offer several advantages to publishers, including:

·       Access to a wider range of advertisers: SSPs establish connections with numerous advertisers, expanding the pool of potential buyers for ad inventory.

·       Simplified management of multiple ad networks: SSPs help publishers navigate the complexity of working with multiple ad networks and exchanges simultaneously.

·       Granular reporting: SSPs provide detailed reporting and data analysis, enabling publishers to optimise their inventory and make informed decisions.

·       Dynamic price floor: SSPs allow publishers to set flexible price floors, maximising their revenue potential.

·       Brand safety: SSPs can enhance brand safety by selectively offering inventory to specific buyers or channels, blocking unwanted ads from appearing on publishers' websites.

Leading SSP Companies in the Programmatic Ecosystem Several SSP companies play significant roles in the online advertising ecosystem.

Some prominent examples include:

·       Google Ad Manager (formerly DoubleClick for Publishers): A comprehensive ad serving platform hosted by Google that streamlines ad management.

·       AppLovin MAX (formerly MoPub): Amobile-focused SSP that provides monetisation solutions for app publishers and developers.

·       Xandr (formerly AppNexus): A cloud-based software platform aimed at optimising programmatic online advertising.

·       Magnite (formerly Rubicon Project): A large SSP that offers additional services like a DSP, Private Marketplace (PMP), and Programmatic Guaranteed (PG).

·       PubMatic: A platform empowering independent app developers and publishers to control and maximise their digital advertising businesses.

Choosing the right supply-side platform depends on factors such as strategy, goals, budget, campaign type, and target audience. It's crucial for publishers to select aright supply side platform that aligns with their specific needs and helps maximise their revenue potential.


Supply-side platforms play a vital role in programmatic advertising, enabling publishers to optimise their ad inventory management and connect with a wider range of advertisers. By leveraging the features and benefits offered by SSPs, publishers can enhance their revenue, gain valuable insights, and simplify the complexity of the programmatic ecosystem.

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