Retail media is the fastest-growing ad channel in digital, poised to reach $100 billion as ad spend in the US retail segment has passed $60 billion in 2025 and is expected to hit $70 billion in 2026, and is outpacing the digital ad market growth. The top line is the least revealing number in retail media at the moment, though, it’s a budget shift number. According to the 2026 survey of 166 retail media advertisers, 52% of marketers expect to increase the amount of display spend they move from open-web DSPs to retail media DSPs, with 47% planning a net increase in budget for connected TV, 50% saying the same with regard to social commerce and 40% with regard to total DSP spend. This is not only about retail media money; it’s about retail media money flowing through a specific mechanism: the demand side platform.
This is a shift worth understanding precisely, because retail media’s first phase and its next phase are powered differently. The first phase was onsite sponsored search and display, the ads on the retailer’s own website, which was the easy money of retail media and is now saturating. The next phase, the $20-billion-plus that takes retail media toward $100 billion, is moving offsite, into CTV, programmatic open web, and paid social, where the retailer’s first-party audience data is activated against inventory beyond the retailer’s own properties. And the engine that activates retailer data against offsite inventory is the DSP. Retail media’s growth story is, increasingly, a DSP story, because the DSP is how retail media escapes the ceiling of onsite inventory and reaches the audiences wherever they watch, read, and scroll.
For founders working with a Custom Demand-Side Platform Development Company, this is the intersection that matters most in AdTech right now. The DSP is no longer just a tool for buying open-web programmatic; it is becoming the activation engine for retail media’s offsite expansion, and that role is reshaping what a DSP has to do. Here is the role DSPs play in retail media’s growth, and why the demand-side platform is central to the path toward $100 billion.
Why Retail Media’s Growth Became A DSP Story
The connection between retail media’s growth and the DSP follows from where the growth is actually coming from. Onsite retail media, the sponsored search and display on the retailer’s own site, was the category’s foundation, but onsite inventory is finite and is saturating as more advertisers compete for the same limited placements. A retailer’s website has only so many sponsored slots, and once they are sold, onsite growth slows. The category cannot reach $100 billion on onsite inventory alone, which is why the growth has moved offsite.
Offsite retail media is fundamentally a DSP activity. Activating a retailer’s first-party audience data against inventory beyond the retailer’s properties, the open web, CTV, social, requires a demand-side platform to do the buying and the targeting, because that is what a DSP is: the technology that buys inventory programmatically across channels and applies audience data to the targeting. When a brand wants to reach a retailer’s shopper audience on connected TV or across the open web, it activates that audience through a DSP. The offsite expansion that is driving retail media toward $100 billion is therefore, by its nature, DSP-driven, and the budget-shift data confirms it: advertisers are moving display dollars out of open-web DSPs and into retail media DSPs specifically because the retail media DSP is where the retailer audience activation happens.
A Custom Demand-Side Platform Development Company building for this reality recognizes that the DSP is the load-bearing technology of retail media’s next phase. The supply side, the retailer building and exposing its first-party data as a targeting layer, is essential, but the demand side, the DSP that activates that data against offsite inventory, is the engine that turns the exposed data into spent budget and reached audiences. Retail media’s growth runs through the DSP.
- Onsite saturates, offsite is the growth: Finite onsite inventory caps the category’s growth, so the path to $100 billion is offsite activation of retailer data, which is fundamentally a DSP activity.
- The DSP is the activation engine: Activating retailer first-party audiences against open web, CTV, and social inventory requires a DSP, making the demand-side platform the load-bearing technology of retail media’s next phase.
What A Retail Media DSP Does That an Open-Web DSP Does Not
The reason advertisers are shifting budget from open-web DSPs into retail media DSPs is that a retail media DSP does things an open-web DSP cannot, and understanding those differences clarifies what the DSP’s role in retail media actually requires. A retail media DSP is not just an open-web DSP pointed at retailer inventory; it is a demand-side platform built around commerce data and closed-loop measurement.
The first difference is commerce data integration. A retail media DSP activates the retailer’s first-party purchase and shopper data, the record of what people actually bought, browsed, and added to cart, which is a fundamentally more powerful targeting signal than the inferred interest data open-web DSPs traditionally relied on. Targeting a shopper who actually purchased a competing product is different from targeting a shopper inferred to be interested in the category, and the commerce data is what makes retail media targeting precise. The second difference is closed-loop measurement: the retail media DSP can tie the ad exposure back to an actual purchase at the retailer, closing the loop between spend and sale in a way open-web programmatic never could honestly do. This closed-loop attribution is the measurement breakthrough that makes retail media accountable, and it is core to the retail media DSP.
The third difference is the onsite-offsite bridge. The most powerful retail media DSPs bridge the retailer’s onsite inventory and the offsite programmatic world, letting an advertiser run a full-funnel campaign that connects the sponsored product ad on the retailer’s site to the offsite CTV and open-web extension, all tied to the same commerce data and the same closed-loop measurement. An AdTech Software Development effort building a retail media DSP designs around these three capabilities, commerce data activation, closed-loop measurement, and the onsite-offsite bridge, because they are what distinguish a retail media DSP from a generic programmatic buying tool and what advertisers are shifting their budgets to access.
- Commerce data over inferred interest: A retail media DSP activates real purchase and shopper data, a far more precise targeting signal than the inferred interest data open-web DSPs traditionally used.
- Closed-loop and the onsite-offsite bridge: The retail media DSP ties ad exposure to actual purchase and connects onsite retailer inventory to offsite CTV and open-web extension under one commerce-data-driven campaign.
The Convergence: Retailers Opening Data into DSP Workflows
A defining development of 2026 is that the largest retailers are actively opening their first-party data into the DSP workflows advertisers already use, which accelerates the DSP’s central role in retail media. Rather than forcing advertisers into closed retailer-owned tools, the major retail media networks are making their audiences and closed-loop measurement available through leading demand-side platforms, so advertisers can activate retailer data in the platforms they already operate.
The most transparent example is Walmart Connect, which began by integrating Walmart content and its closed-loop measurement into current purchase workflows for advertisers, starting with connected TV supply, via a major DSP and supply-side technology. Criteo’s Commerce Max DSP connects onsite retail media and offsite programmatic, tieing both together with a first-party commerce data set for hundreds of retailers. The trend continues: Retailers are showing their data and the data is being activated by advertisers, typically via the DSP workflows that advertisers are already using, rather than in other closed tools.
This convergence is what makes the DSP central rather than peripheral to retail media. The retailer’s first-party data is the asset, but the DSP is the means of activation, and as retailers open their data into DSP workflows, the DSP becomes the place where retail media buying actually happens. The supply side exposes the data; the demand-side platform activates it; and the advertiser’s budget flows through the DSP. A Custom Demand-Side Platform Development Company building retail media DSP capability is building the activation layer that this convergence is making indispensable.
What Building Retail Media DSP Capability Requires
For a business building or evaluating retail media DSP capability, the requirements follow from the DSP’s role as the commerce-data activation engine. The platform has to integrate retailer first-party commerce data as a targeting layer, support closed-loop measurement that ties exposure to purchase, bridge onsite and offsite inventory under unified campaigns, and activate the retailer identity graph against open-web, CTV, and social inventory. These are capabilities beyond a generic open-web DSP, which is precisely why retail media DSPs are a distinct category attracting distinct budget.
The build-versus-buy question that applies to DSPs generally applies here too: a business can build retail media DSP capability through a full custom build, a bidder-as-a-service architecture, or a white-label platform, depending on its scale and technical capacity, and the right choice depends on the same factors that govern any DSP build decision. What is specific to retail media is that the capability set centers on commerce data and closed-loop measurement, so whichever build path a business takes, the platform has to be architected around the commerce-data activation and closed-loop attribution that define the retail media DSP. The DSP that has these capabilities participates in the budget shift toward retail media; the one that does not is competing for the open-web display dollars that advertisers are actively moving away from.
The Bottom Line
The next stage in the growth to $100 billion becomes increasingly a DSP story as the growth here is offsite, and the demand-side platform is the means of driving retailer first-party data against those multiple inventories sets namely CTV, open-web, and social media. The shift data is tangible evidence of the DSP’s centrality: advertisers are transferring display dollars from open-web DSPs to retail media DSPs, since all of the following activities are taking place within the retail media DSP: retailer audience activation, targeting using commerce data, and closed-loop measurement. The supply side displays the retailer’s information, while the demand-side platform converts that information into ‘spent budget’ and ‘reached audiences.
A Custom Demand-Side Platform Development Company that understands this builds the retail media DSP capability the category’s growth requires, the commerce-data integration, the closed-loop measurement, the onsite-offsite bridge, and the identity-graph activation that distinguish a retail media DSP from a generic programmatic tool. As the largest retailers open their first-party data into the DSP workflows advertisers already use, the DSP moves from the periphery of retail media to its center, the activation layer through which the path to $100 billion actually runs. Retail media’s growth story is being written on the demand side, and the DSP is the technology writing it.
