SSP, stands for Supply Side Platform, is am advanced technology platform created to assist publishers to sell, manage, and optimize online advertising space (ad inventory programmatically).
Publishers can sell ad space to Ad Exchanges, Ad Networks, and DSPs and monetize their website and apps.
SSP is an equivalent of the DSP. The main difference is that SSPs used by publishers, and DSPs used by advertisers. Advertisers use DSPs to buy ads as efficiently and cheaply as they can, while publishers do the opposite and use SSPs to maximize the prices of their inventory they’re going to sell.
SSP is an indispensable part of the programmatic advertising ecosystem. With SSPs, publishers can do three big things: open up their inventory to a larger range of potential buyers through real-time bidding, say which advertisers can or can’t purchase their inventory and set the minimum prices for which their inventory can be sold to certain buyers.
How does SSP Work?
Publishers work with SSPs to sell their inventory programmatically. They often have several SSPs set up so that they can create competition between SSPs and drive up the price they sell inventory for. On average, publishers work with around 4-5 SSPs.
The publisher signs up with the SSP, and defines the inventory they’ll sell through the SSP. This will include parameters such as site names, sections, any data, floor pricing, ad sizes, etc. This can be as simple or as complicated as the publisher likes.
The SSP puts the ad request into an auction, which DSPs are invited to participate in.
The DSPs respond with bids, and the SSP returns the winning bid to the publisher.
The publisher will have a few different methods to deal with the bid:
Internal ad-server SSP – ad servers have an SSP built into the ad server, so a winning bid is turned into an ad impression without intervention from the publisher.
Prebid – publishers use prebid or other header bidding technologies – to receive bids from several different SSPs at once, and to choose the best SSP to serve that impression. prebid.org for more information.
Waterfalls and passback – publishers use their ad server to make a request to the SSP, then if the SSP fills with an ad they display it; if not, they run a ‘passback’ tag, and send the impression off to another SSP to attempt to fill it. Publishers may repeat this several times. Many publishers have moved away from this in favor of the above 2 options.