Short answerAn SSP (supply-side platform) is software that publishers use to sell their ad space. It offers each impression to many buyers at once, runs or joins the auction, applies the publisher's rules such as floor prices and blocked categories, and pays for the impressions that are sold.
For a website owner, the SSP is the part of programmatic advertising that turns traffic into revenue. This article explains what a supply-side platform does, how it helps earn more from the same audience and what to look at before you connect a site.
What does an SSP do?
An SSP works for publishers, the mirror image of a DSP that works for advertisers. When a visitor opens a page, the SSP:
Receives the ad request from the site's ad code or video player.
Describes the impression in a bid request: format, size, page, country, device and other anonymous signals.
Offers it to buyers — connected DSPs, ad exchanges and direct advertisers — usually through OpenRTB.
Applies the publisher's rules, such as a floor price and blocked advertisers or categories.
Picks the winner and returns the ad to the page.
Counts and pays for the impressions that were sold.
The more buyers compete for an impression, the higher the price usually is. That competition is the main reason publishers use SSPs instead of selling to a single advertiser.
How does an SSP increase publisher revenue?
More demand per impression. Dozens of buyers bid on the same slot instead of one.
Higher fill rate. If one buyer passes, another may still want the impression, so fewer slots stay empty.
Floor prices. The publisher can refuse bids below a minimum value.
Header bidding support. Some SSPs join Prebid auctions, which lets them compete with other demand in the same moment.
How does a publisher connect to an SSP?
Most SSPs and ad networks offer one or more of these options:
Method
Typical use
JavaScript tag or script
Banners, interstitials, popunders on any website
VAST tag
Video ads inside your own video player. See VAST vs VPAID
Prebid adapter
Sites that already run header bidding
OpenRTB connection
Platforms and networks that trade server to server
Whatever method you use, add the lines your SSP gives you to your site's ads.txt file. Many buyers will not bid on inventory that is not declared there.
What should a publisher check before choosing an SSP?
Statistics and support. Real-time reports by format, GEO and device, and a manager you can reach.
Transparency. Does the SSP publish a sellers.json file? It shows buyers that your inventory is sold through a known, verifiable path.
SSP and ad network: what is the difference?
An ad network historically bought inventory from publishers and resold it to advertisers, often at fixed prices. An SSP is a technology layer that sells each impression in an auction. Today the difference is mostly in emphasis: many ad networks run their own SSP, and some platforms combine both sides. Wizads, for example, operates an SSP for publishers, a DSP for advertisers and its own ad server, so advertisers and publishers meet on one platform.
How to start with the Wizads SSP
Publishers with at least 1,000 unique visitors per day can join the Wizads SSP. Moderation takes up to 24 hours. You add a script or a VAST tag, choose formats, and get paid for every ad impression on the CPM model, with real-time statistics on fill rate, CTR, GEO, viewability, formats and devices.
Frequently asked questions
Do I need several SSPs?
Not necessarily. More SSPs can mean more competition, but each additional script adds weight to the page. Many publishers start with one or two partners, measure revenue per thousand visitors, then add more only if it pays off.
What is the difference between SSP and DSP?
The SSP sells impressions for publishers, the DSP buys them for advertisers. Our article DSP vs SSP compares them side by side.
Is an SSP the same as an ad server?
No. An ad server stores creatives and decides which one to show, while an SSP runs the sale of impressions to outside buyers. Large publishers often use both.
Wizads is an advertising network with its own DSP, SSP and ad server. Our team writes about programmatic advertising, website monetization and buying traffic.
