Offsite Retail Media Explained: how retailer data reaches other screens, and how sales come back

Every offsite campaign answers one question first: where does the auction happen? The answer decides who controls bids, fees and reporting.

Route 1 gives the retailer the most control and the buyer the least choice of tools. Route 2 is the reverse: the agency keeps its seat, fees and frequency caps, and buys the data like any other segment. Route 3 moves the packaging to the sell side. Walmart says Magnite's technology can support audience decisioning across several DSPs through a Walmart-controlled data model (Walmart Connect, 28 May 2026). A curated marketplace of this kind is sold through a deal ID. Route 4 reaches walled gardens that no open DSP can buy. Large retailers now run all four at once.

The two clean room steps are the core of offsite. The first step turns customers into a segment a partner can target. The second step joins ad exposures to purchases. In both, the retailer's records stay in a controlled environment and only aggregates leave.

Identity is the glue. Kroger's link with Display & Video 360 matches exposures and transactions through LiveRamp's pseudonymous RampID, with MetaRouter routing conversion events. PPC Land reports that neither Google, Kroger nor the brand handles raw personal data in that flow (PPC Land, 24 March 2026). Amazon does the same job in-house: Amazon Marketing Cloud is a clean room built on AWS Clean Rooms (Amazon Ads, accessed 9 November 2026). The design choices are compared in clean room architectures compared, and the vendors in the LiveRamp Clean Room and Amazon Marketing Cloud profiles.

Walmart is the clearest case of a network moving from Route 1 to all routes. It launched its DSP with The Trade Desk in 2021, and that exclusivity ended in fall 2025. In April 2026 it added Connect Select, a curated CTV marketplace inside Walmart DSP with VIZIO, Paramount and Warner Bros. Discovery inventory and four SSPs (Walmart Connect, 27 April 2026).

On 28 May 2026 it opened VIZIO inventory to Yahoo DSP buyers through Magnite, still a closed proof of concept that Walmart says will widen later (Walmart Connect, 28 May 2026). On 11 June it added Display & Video 360, starting with YouTube campaigns (Google, 11 June 2026). The Walmart Connect profile covers how to buy each route.

Amazon keeps offsite inside its own platform. Since 29 September 2026, DVA+ places ads across streaming TV, online video, display and audio "on Amazon properties and the open internet" (Amazon Ads, 29 September 2026). Advanced settings let experienced buyers pick deals and supply sources. DVA+ began rolling out in late October 2026. The trade-off is clear: one login and one measurement system, but no route through an outside DSP. Fees and seats are covered in DSP pricing explained.

Kroger planned this path early. In June 2023, when it moved its self-serve ad tech in-house, it said the platform would later extend to offsite programmatic and streaming partners such as Disney and Roku (AdExchanger, 28 June 2023). In March 2026 it joined Google's Commerce Media Suite. Brands can now buy Kroger audiences on YouTube and third-party display in Display & Video 360 and see sales by SKU (PPC Land, 24 March 2026).

Instacart sells offsite through eight named platforms, in self-service or managed form (Instacart, accessed 9 November 2026). Its Trade Desk route bundles Instacart audiences and measurement into the DSP "no IOs necessary". Instacart also says it was the first retail media partner with end-to-end capabilities inside TikTok Ads Manager (company claim). Partner programmes like this let a brand reach Instacart shoppers without a new platform login.

Offsite reports usually show three numbers. Attributed sales count purchases by exposed shoppers within an attribution window. New-to-brand share counts buyers who had not bought the brand at that retailer recently; Walmart, for example, uses a 12-month lookback (Walmart Connect, 27 April 2026). Incrementality compares exposed shoppers with a holdout group that saw no ad.

The first two numbers are easy to inflate. A shopper who would have bought anyway still counts as attributed. That is why buyers now ask for holdout tests. In IAB Europe's 2026 survey, demand for return on ad spend fell to 49% of European buyers, from 89% a year earlier (PPC Land on IAB Europe, 6 November 2026).

Offsite also moves store sales. A vendor study by Incremental of 150,000 campaigns found 42% of the incremental effect of offsite video arrived as in-store purchases, against 7% for onsite search (PPC Land, 2 October 2026). A report limited to online sales will undercount offsite. Standards for windows and metrics are summarised in retail media measurement standards explained, and the store side in in-store retail media.

Buyers increasingly want onsite and offsite results side by side. A brand that pays for sponsored search and a CTV flight at the same retailer wants to know whether the CTV ad drove the search click. Few networks report that way yet. In IAB Europe's 2026 survey, 31% of sellers offered unified onsite and offsite reporting, while 66% of European buyers asked for unified online and offline reporting (PPC Land on IAB Europe, 6 November 2026).

Two set-ups close the gap. One runs onsite and offsite through the same buying tool, as Dollar General is doing by bringing its onsite inventory into The Trade Desk through Kevel (Marketing Dive, 4 May 2026). The other keeps separate tools but writes every exposure into the same clean room, so one query can join them. The first is simpler for buyers. The second keeps more choice of partners.

1. Which route? Decide whether you buy in the retailer's DSP, your own DSP, a curated deal or a platform. Each sets different fees and controls.
2. What does the data cost? Data fees, platform fees and measurement fees are rarely public. Ask for each line in writing.
3. What is the match rate? A segment of one million loyalty IDs may reach far fewer people after matching.
4. Which sales count? Confirm online and store sales are both included, and the window used.
5. Is there a holdout? Ask for an incrementality design before launch, not after.
6. Who owns the output? Agree which reports and audience insights you can keep after the campaign.

1. Marketing Dive, "Walmart Connect expands offsite advertising ambitions with Yahoo, Magnite" (1 June 2026). https://www.marketingdive.com/news/walmart-connect-expands-offsite-advertising-ambitions-with-yahoo-magnite/821575/
2. The Desk, "WARC: Retail media ad market to top $200 billion as growth slows" (19 August 2026). https://thedesk.net/2026/08/warc-retail-media-ad-market-to-top-200-billion-as-growth-slows/
3. Walmart Connect, "New pathways to programmatic CTV at scale" (27 April 2026). https://www.walmartconnect.com/resources/articles/2026/new-pathways-to-programmatic-CTV-at-scale
4. Google, "Google Display & Video 360 and Walmart Connect team up" (11 June 2026). https://blog.google/products/marketingplatform/360/walmart-connect/
5. PPC Land, "Kroger joins Google's Commerce Media Suite to unlock SKU-level sales data on YouTube" (24 March 2026). https://ppc.land/kroger-joins-googles-commerce-media-suite-to-unlock-sku-level-sales-data-on-youtube/
6. PPC Land, "Albertsons brings grocery shopper data to YouTube via Google's ad suite" (28 April 2026). https://ppc.land/albertsons-brings-grocery-shopper-data-to-youtube-via-googles-ad-suite/
7. Amazon Ads, "Amazon Ads introduces Full-Funnel Campaigns, DVA+, and enhanced chat experience in AI-powered ad platform, Amazon Ads Agent" (29 September 2026). https://advertising.amazon.com/library/news/amazon-ads-agent
8. Amazon Ads, "Amazon Marketing Cloud" (accessed 9 November 2026). https://advertising.amazon.com/solutions/products/amazon-marketing-cloud
9. Instacart, "Off-platform" advertising solutions (accessed 9 November 2026). https://company.instacart.com/ads/off-platform
10. AdExchanger, "Kroger Is Bringing Its Retail Media Ad Tech In-House" (28 June 2023). https://www.adexchanger.com/retail-media/kroger-is-bringing-its-retail-media-ad-tech-in-house/