Offsite describes advertising that a retailer, marketplace, or commerce platform sells against its own first-party customer data but delivers somewhere else: on open-web publisher sites, in mobile apps, on connected television, or inside social platforms. The retailer supplies the audience and, usually, the sales measurement. Someone else supplies the impression. That division of labor is the entire point of the format.

It exists because the two halves of a retail media network are mismatched in size. A grocery chain may know what several million households bought last week, but its website and app produce a finite number of ad slots, nearly all of them close to the point of purchase. Offsite converts the surplus data into media that can run anywhere, and it moves retail media up the funnel, where reach rather than shelf position determines the outcome. IAB Europe's 101 Guide to Retail and Commerce Media treats off-site as one of three activation environments alongside on-site and in-store, defining it as delivery on third-party inventory such as video, social, display, and addressable or connected television.

How an offsite campaign is assembled

The starting point is a segment built from transaction records, loyalty identifiers, or logged-in browsing. Because those records are tied to email addresses, phone numbers, or account IDs rather than to cookies, they must be converted into something a bidding system can match. Identity vendors do that translation. When Kroger Precision Marketing joined Google's Commerce Media Suite, the SKU-level conversion reporting ran through LiveRamp and MetaRouter, with MetaRouter handling server-side event routing and LiveRamp handling identity resolution.

Activation then follows one of four paths. The first is the retailer's own demand-side platform, the model Amazon established and Walmart replicated. The second is a third-party DSP: Walmart Connect made its shopper audiences available inside Yahoo DSP in May 2026, routed through Magnite supply, then extended the same data into Display and Video 360 for YouTube inventory on June 11, 2026. The third is a walled garden, where the retailer pushes segments into Meta or Google Shopping and accepts whatever measurement the destination allows. The fourth is curation, in which the audience is packaged with supply and creative into a Deal ID that a buyer drops into an existing DSP seat. Criteo and TripleLift described that workflow in an April 2026 technical explainer: four creative assets in, one deployed Deal ID out.

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Inside the auction, an offsite impression looks ordinary. The segment travels as a list of pseudonymous identifiers loaded into the DSP, and the bid request carries no marker identifying it as retail media. What differs is the reconciliation afterward, when exposure logs are matched back against purchase records inside a clean room or a permissioned data feed. Attribution windows are set by the network rather than by the buyer, and they vary. The in-store standards issued by the IAB and IAB Europe recommend reporting across three periods, covering 30 days before exposure, the campaign itself, and 30 days after, but no equivalent single convention governs offsite digital sales. Two networks that chose different windows produce numbers that do not mean the same thing.

Format mix follows buyer habit rather than retailer capability. IAB Europe research covered by PPC Land found display leading offsite investment at 58% of buy-side spending, social at 55%, and connected television at 31%, against only 19% of retailers actually enabling CTV placements.

Measurement is the third component and the one retailers use to justify the premium. Because the network owns the transaction log, it can report whether an exposed household later bought the advertised item, online or in a store. Walmart Connect reported a median of 44% new-to-brand buyers across offsite CTV campaigns during a fiscal year running February 1, 2025 to January 31, 2026, and a 52% new-to-brand rate from offsite display, both figures self-reported from its own first-party data.

Operationally, the sell side is the retail media network's commercial team plus a technology partner. Criteo, Epsilon Retail Media, Koddi, Topsort, and Symbiosys all sell offsite infrastructure to retailers that will not build it. MediaMarktSaturn's first offsite program, announced at DMEXCO in September 2025, used Unlimitail as the commercial partner and Epsilon as the technology layer. On the buy side sit brand shopper-marketing teams and, increasingly, the same programmatic traders who buy everything else.

Pricing and commercial structure

Offsite is usually sold on CPM for display and video and on CPC for search-style product ads, but marketplaces have built a different model in which the platform runs the media itself and bills sellers a share of attributed revenue. Etsy's Offsite Ads, announced in February 2020, charges 15% of an attributed order for shops under $10,000 in trailing twelve-month sales and 12% for shops above it, capped at $100 per order, with participation mandatory above the threshold and a 30-day attribution window. eBay launched an optional equivalent in 2021. Amazon took a third route: when it extended Sponsored Products to third-party apps and websites in October 2023, participation was automatic and the existing cost-per-click bid carried over, with no separate offsite line item. Control arrived later, through an Off-Amazon ad serving column added to Sponsored Products bulksheets on June 8, 2026.

The margin structure differs sharply from onsite. Onsite inventory costs the retailer almost nothing to produce. Offsite requires buying media, which compresses the take rate and makes offsite growth less profitable per dollar than the headline revenue figures suggest.

Origin and evolution

The mechanism predates retail media. Publishers sold audience extension through the 2010s, letting advertisers reach a title's readers on cheaper inventory elsewhere. Retail media inherited the technique and improved the data underneath it, swapping inferred interest for observed purchase.

Scale came slowly. EMARKETER estimated that on-site placements accounted for 94.5% of US retail media spending in 2018 and 85.5% in 2023, with the on-site share projected to remain above 80% through 2027. Standardization followed the money. The IAB and the Media Rating Council released a draft of the Retail Media Measurement Guidelines on September 13, 2023, finalized in January 2024; IAB Europe published its own on-site and off-site measurement standards in April 2024 and opened a second version to public comment on October 9, 2025.

Platform integration is the most recent phase. Google added retail media support to Search Ads 360 in March 2024 with Lowe's as an early tester, then assembled a Commerce Media Suite inside DV360 that by mid-2026 included Kroger, Costco, Dollar General, Best Buy Ads, Shipt, and Albertsons. The Trade Desk moved the other way, opening onsite retail inventory to programmatic buyers through Koddi in October 2025.

Disambiguation

Offsite SEO, more often called off-page SEO, refers to backlinks and external signals affecting organic search rankings. It shares no infrastructure with offsite advertising.

Offsite Ads as a marketplace fee describes the Etsy and eBay programs above, where the platform buys the media and the seller pays only on attributed sales. This is a billing arrangement, not an audience product.

Audience extension is the publisher-side ancestor: same architecture, but the seed data is content consumption rather than purchase.

Onsite covers sponsored products, sponsored brands, and display within the retailer's own site or app. In-store covers screens, audio, and shelf activations, and is governed by a separate IAB standard published in December 2024.

Limitations and disputes

The central problem is that offsite ads frequently sell products at retailers other than the one running the campaign. Incremental's June 2026 analysis of more than 150,000 campaigns and $350 million in spend found that siloed attribution misses between 36% and 53% of total retail media impact, with offsite video the worst case at an estimated 67% to 80%. On the study's indexed figures, offsite DSP campaigns delivered $0.77 of incremental return at the advertising retailer and $0.87 elsewhere.

Forecasts disagree on how fast offsite is growing. EMARKETER projected 27.1% growth for US off-site retail media in 2025 to $13.52 billion in an August 2024 publication, but a November 2024 forecast from the same firm put off-site growth for 2025 at 42.1%. Neither figure has been reconciled publicly.

Vendor case studies remain weakly evidenced. Criteo reported that shoppers exposed to combined onsite and offsite advertising in an HP and Costco campaign showed an 855% uplift in conversion rates, a self-reported figure with no disclosed control methodology. Standards adoption is also incomplete: IAB Europe research found 70% of buyers citing the absence of retail media standards as a barrier to investment. Consent adds a further constraint, since moving shopper identifiers to third-party inventory requires a lawful basis that survives the transfer.

Recent developments

Amazon updated its off-Amazon support documentation on August 4, 2026, and began placing Sponsored Products with Amazon Influencer Program creators on August 10, again on automatic participation. TikTok Shop published documentation on August 6, 2026 for an off-site performance report that excludes Amazon, Walmart, and offline channels. Earlier in the summer, Uber Advertising launched Offsite Ads into Meta and Google Shopping on June 16, 2026, and DoorDash routed global offsite capability through Symbiosys as part of a June 4, 2026 platform expansion.

Timeline

  • 2018: On-site placements account for 94.5% of US retail media spending, per EMARKETER
  • February 2020: Etsy announces Offsite Ads, mandatory above $10,000 in trailing sales; billing begins April 14, 2020
  • 2021: eBay launches an optional offsite advertising program
  • October 2023: Amazon extends Sponsored Products to Pinterest, BuzzFeed, Hearst Newspapers, Raptive, and Ziff Davis titles
  • September 13, 2023: IAB and MRC release draft Retail Media Measurement Guidelines for public comment
  • January 2024: IAB and MRC publish the final guidelines
  • March 2024: Google adds retail media to Search Ads 360, with Lowe's in beta
  • April 2024: IAB Europe publishes on-site and off-site retail media measurement standards
  • December 2024: IAB and IAB Europe finalize separate in-store standards
  • May 2025: Google names Costco, Intuit, Regal Cinemas, and United Airlines as DV360 commerce media partners
  • September 2025: MediaMarktSaturn launches its first offsite program with Unlimitail and Epsilon
  • October 9, 2025: IAB Europe opens Commerce Media Measurement Standards V2 for comment
  • January 2026: Commerce Media Measurement Standards V2 finalized
  • March 24, 2026: Kroger Precision Marketing joins Google's Commerce Media Suite with SKU-level reporting
  • June 11, 2026: Walmart Connect audiences reach DV360 for YouTube
  • June 15, 2026: Incremental publishes cross-retailer halo findings
  • August 10, 2026: Amazon begins serving Sponsored Products through Influencer Program creators

Summary

Who: Retail media networks and commerce platforms including Amazon, Walmart Connect, Kroger Precision Marketing, Albertsons, MediaMarktSaturn, Uber, DoorDash, Etsy, and eBay, working with technology partners such as Criteo, Epsilon Retail Media, Koddi, Topsort, Symbiosys, LiveRamp, and MetaRouter, and with DSPs including Amazon DSP, Walmart DSP, Display and Video 360, Yahoo DSP, and The Trade Desk.

What: Advertising sold by a retailer or commerce platform using its own first-party shopper data but delivered on inventory it does not own, spanning open-web display, online video, connected television, social, audio, and digital out-of-home.

When: Present in publisher audience extension through the 2010s, formalized for retail media between 2020 and 2024 as Etsy, eBay, and Amazon launched offsite programs and the IAB, MRC, and IAB Europe published measurement standards, and consolidated into mainstream DSP workflows across 2025 and 2026.

Where: Third-party websites, mobile apps, streaming environments, and social platforms, with buying concentrated in the United States and Europe. European retail media reached 13.7 billion euros in 2024 on IAB Europe figures, and the share of buyers putting more than 41% of digital spend into offsite rose from 30% to 46%.

Why: Onsite retail inventory is finite and lower-funnel, while retailer purchase data has value wherever an impression can be bought. Offsite converts that data into reach, but it also moves the ad away from the retailer's own environment, which is where its measurement problems begin.