Glossary/Programmatic/DSP vs SSP
DSP vs SSP: how the buy side and sell side of programmatic differ
How demand-side and supply-side platforms differ, how they meet in every auction, and what publishers should do on each side.
Written by Samhub with the help of AI·Updated 13 Oct 2026·3 min readA DSP (demand-side platform) buys ad impressions on behalf of advertisers. An SSP (supply-side platform) sells them on behalf of publishers. They meet in the auction for every programmatic impression.
DSP vs SSP at a glance
| DSP | SSP | |
|---|---|---|
| Works for | Advertisers and agencies | Publishers |
| Goal | Buy the right impressions at the lowest price | Sell each impression at the highest price |
| Decides | Whether and how much to bid | Which bid wins, above the floor |
| Examples | The Trade Desk, DV360, Amazon DSP | Magnite, PubMatic, Google Ad Manager |
How they work together
The SSP offers the impression
It sends a bid request to many DSPs.
DSPs evaluate and bid
Each one checks the impression against its campaigns.
The SSP picks the winner
The best bid above the floor wins.
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What publishers should do
On the SSP side, pass audience data and set up deals. On the DSP side, make sure buyers know your audiences exist and can find them with the same names in every SSP.
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Frequently asked questions
Some large ad tech companies run both, which is why buyers and sellers watch fees and conflicts closely.
Not to sell. Publishers use SSPs, but they should understand how DSPs value impressions.
Between them. It runs the auction, and today it is usually part of the SSP.
Both platforms take a share of the media spend, so the publisher receives less than the advertiser pays.
Related terms
The software advertisers use to buy impressions.
The software publishers use to sell impressions.
An auction for every single impression.
The technology used to buy, sell and measure ads.
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