Retail Media Platforms 2026: Marketplace vs Retailer Picks

Last updated: April 26, 2026

Marketplaces and retailers need fundamentally different retail media platforms in 2026. Marketplace operators monetize seller competition for placement and require multi-seller self-serve tools, second-price auctions, and seller wallet systems; direct retailers monetize brand budgets against first-party shopper data and need closed-loop attribution, identity layers, and brand advertiser onboarding. Choosing a platform built for the wrong model leaves either seller activation revenue or brand demand on the table — and with Amazon and Walmart projected to capture more than 89% of incremental US retail media spending in 2026 (eMarketer, H2 2025), independent operators cannot afford a platform mismatch. For broader context on how retail media reached this point, see the complete guide to retail media evolution.

This article takes a deeper dive into the practical 2026 platform-selection decision: how marketplace and retailer requirements differ, which vendors fit which side of that line, and where Osmos's Osmosphere retail media operating system sits as the cross-model independent option.

Why Platform Choice Differs by Business Model

A retail media platform is the technology stack that turns a retailer's or marketplace's owned digital surfaces — search results, product detail pages, category browse, in-store screens, and offsite extensions — into auctioned advertising inventory tied to first-party shopper signals. The definition is the same on paper for marketplaces and retailers. The economics are not.

Marketplace retail media is seller-funded advertising on marketplace-owned inventory using browse and purchase data, with self-serve tools that turn thousands of sellers into active advertisers. The operator monetizes seller competition for placement on its own SKUs.

Retailer-direct retail media is brand-funded advertising on a retailer's own inventory and offsite reach, activated against the retailer's first-party customer data. The operator monetizes a smaller set of larger brand-advertiser budgets against owned shopper signals.

That distinction drives nearly every meaningful platform decision: who can self-serve, what data activates targeting, how attribution closes, what the auction looks like, and how the take-rate flows back to the operator. The market size and trajectory make the stakes clear. US retail media ad spend will reach $69.33 billion in 2026, up from $58.79 billion in 2025 — a 17.9% increase (eMarketer, H2 2025). Globally there are now over 200 retail media networks across grocers, specialty retailers, marketplaces, and delivery services (RMIQ 2025 Retail Media Market Guide). Off-site retail media is projected to grow at roughly twice the rate of on-site through 2026 per eMarketer's H2 2025 forecast, and the IAB Europe Commerce Media Measurement Standards V2 — published in January 2026 with a six-month transition window running until the end of July 2026 — finally gives both sides of the market a shared measurement vocabulary (IAB Europe, 2026).

The Skai 2026 State of Retail Media report adds the operator-side context: brands today manage an average of six retail media networks and expect to expand to eight by year-end 2026, while three-quarters of brands report measurement capabilities are still weak or just adequate (Skai with Stratably, 2026). The platform an operator picks determines whether it can plug cleanly into that fragmented buyer landscape — or sit on the outside of it.

How Marketplace Retail Media Platforms Work

Marketplace retail media is, at its core, a competition mechanic. Sellers bid for visibility against other sellers selling the same or substitute SKUs on the marketplace's owned surfaces. The platform's job is to run that auction, manage seller funds, and convert as many sellers as possible from passive listing pages into active advertisers.

The benefits compound for the operator. Seller-funded ads improve unit economics because the marketplace already owns the customer relationship and the inventory placement, and ad revenue is incremental to commission. Advertising is now 31% of Flipkart's overall revenues (Storyboard18, 2025) — that is the marketplace ad business no longer behaving like a side revenue stream but as a core monetization line. Mirakl Ads grew advertising spend 258% year-over-year in 2025, reaching $12.7 million across close to 50 marketplace clients including Lowe's and Ulta Beauty (Mirakl, February 2026) — the demand-side proof that marketplace operators can convert seller activity into measurable ad budgets.

The use cases follow the marketplace category mix. Fashion marketplaces carry their own playbook — visual storytelling, lookbooks, livestreaming, and editorial placements that generic FMCG-built ad servers handle poorly. Zalando Marketing Services served over 26,000 campaigns in 2024 across 2,400+ active brand partners, reaching 52+ million active customers across 25 European markets and producing 76.5 million attributed item sales that year (Zalando, July 2025). For fashion-specific campaign execution Osmos's retail media for fashion and beauty marketplaces supports shoppable video, story ads, and beauty-vertical advertiser targeting. India marketplace operators demonstrate the FY25 monetization story most clearly: Flipkart's ad income reached ₹6,317 crore (~$716M USD), up 27% year-over-year, with Amazon India and Myntra reportedly earning ₹8,342 crore and ₹914 crore respectively in the same period as reported by Storyboard18 citing company filings. Grocery and quick-commerce marketplaces — BigBasket in India, Konvy in Thailand, Pick n Pay in South Africa — combine sponsored listings with offsite extensions to reach shoppers off-platform. The marketplace revenue rationale itself is covered separately in retail media as a hidden revenue stream for marketplaces — the focus here is platform selection.

The defining platform requirement is seller-to-advertiser conversion at scale. As Mirakl puts it on its product page, marketplace retail media demands "a simple automated UI that easily transforms marketplace sellers into active advertisers" — not a media-planner's enterprise console, but an in-flow self-serve experience that any seller can use without managed-service hand-holding.

How Retailer Retail Media Platforms Work

Retailer-direct retail media is a different creature. The advertiser set is smaller and richer: CPG brands, beauty and personal care manufacturers, electronics OEMs, and lifestyle brands that already buy media at scale and want to activate against the retailer's purchase, loyalty, and browse data. The platform's job is identity, targeting, and closed-loop measurement — proving that media exposure caused incremental sales.

The benefits are different too. Retailers monetize first-party data they already own; brand advertisers gain access to deterministic shopper signals and SKU-level outcome reporting. Walmart's global ad business grew 46% to nearly $6.4 billion in 2025, with Walmart Connect's US advertising up 33% for the full year and 41% in Q4 2025, while Amazon made $68 billion from advertising in 2025 (Digiday, February 2026). Those are retailer-direct numbers built on first-party data activation.

The use case set spans most of large-format retail. Walmart Connect + Vizio CTV is the clearest 2026 omnichannel proof point: Walmart's NewFronts 2026 announcement scaled the content-to-commerce stack across streaming inventory and demonstrated that 65% of surveyed Walmart customers report CTV ads helped them discover new products (Walmart Corporate, March 2026). Kroger Precision Marketing and Target Roundel are the other two retailer-direct anchors, each running into the billions in annual contribution per publicly reported earnings figures, both built on loyalty card and shopper-data foundations. Specialty and grocery retailers outside the mega-bracket — Tesco Media, Sephora Media Collective, Home Depot Retail Media+ — increasingly run their own first-party data activation layers rather than feeding Big Tech intermediaries. For grocery operators specifically, a grocery retail media platform covers the omnichannel surfaces (in-store screens, onsite, and offsite) that grocery shoppers actually traverse.

The platform requirement that defines retailer-direct work is data activation. Three-quarters of brands report measurement capabilities are still weak or just adequate per the Skai 2026 report, and 86% of commerce media decision-makers in North America and Europe say strengthening measurement and attribution is a high or critical priority. A retailer platform that cannot operationalize first-party data into clean rooms, audience segments, and SKU-level closed-loop outcomes is not competitive against Walmart Connect's omnichannel proposition — full stop.

Key Platform Features: What Marketplaces Need vs What Retailers Need

The features divide cleanly. The table below summarizes the core requirement set. (For deep coverage of how the auction layer scales, see how retail media auctions scale with automation.)

A few features are non-obvious but operator-defining. Seller wallet management — prepayments, credit lines, refunds, currency handling — separates true marketplace platforms from retrofitted retailer tools. Osmos's WalletWise handles this directly. Brand demand generation — drip campaigns, advertiser segmentation, reactivation flows — separates retailer platforms that scale beyond endemic CPG from those that plateau; Osmos's Demand Wise targets that gap. Multi-tenant architecture matters for marketplaces because seller data, billing, and reporting must be isolated by tenant; retailers can run single-tenant stacks because there is one merchant. The IAB Europe 2026 Spotlight also flagged new Flexi Ad Sizes Guidelines for Retail Media Networks — four flexible aspect ratios for display ads across devices, developed in collaboration with Tesco Media — as a meaningful 2026 standardization step for both models.

2026 Platform Landscape: The Best Retail Media Platforms Compared

The best retail media platforms in 2026 fall into three groups: marketplace-native (Mirakl Ads, Topsort), retailer-native (Walmart Connect, Kroger Precision Marketing, Target Roundel), and cross-model independent (Osmos's Osmosphere, Criteo, CitrusAd/Epsilon, plus Amazon's new Retail Ad Service). Below is the head-to-head for the platforms most operators are actively evaluating.

A few platform-by-platform details matter for the decision:

Osmosphere is Osmos's full retail media operating system — Adscape (ad formats: product, display, video, in-store, offsite, story, gamified, carousel), ControlHub (campaign operations), StratEdge (revenue strategy with yield management and BYOT targeting), plus WalletWise, Onboard Pro, Pulse Pro, and Demand Wise. Osmosphere is white-label, IAB certified, and has verified results across grocery (BigBasket India), pharmacy (Apollo 24x7 — 200% revenue growth in two months), beauty (Konvy Thailand — 112% ad revenue increase in two months), and South African retail (Pick n Pay — display ad network live in 5 days). The differentiator is cross-model: marketplace operators get seller self-serve and wallet management; direct retailers get first-party data activation and brand demand tooling — without ecosystem lock-in.

Amazon Retail Ad Service is the platform announcement that changed the third-party retailer landscape. Launched at CES January 2025, it lets retailers embed Amazon's ad technology into their own ecosystems with data kept separate via dedicated AWS systems and AWS Clean Rooms (Amazon Advertising, January 2025). Beta participants include iHerb, Oriental Trading Company, Weee!, and Tilly's. Per Amazon's own framing, "retailers control ad creative, placement, formats, and post-click experiences" — but the AWS dependency is structural, not optional, and the rollout is US-centric (Marketing Dive, January 2025). For mid-sized retailers who do not want to commit their data and infrastructure to AWS, Osmos's omnichannel retail media platform is the white-label alternative.

Walmart Connect is the most aggressively positioned retailer-native platform of 2026, with the Vizio CTV partnership creating an omnichannel closed-loop story (in-store transaction data plus streaming TV viewership). Walmart's growth and AI partnership posture is what practitioners are talking about. As Mike Feldman, SVP of Commerce at Flywheel, told Digiday in early 2026, "Walmart is doing so many good strategic moves...they are so open for business in the AI space." Chris Rigas, VP Media at Markacy, framed the gap honestly: "Walmart is still working on turning it into full-funnel advertising." Both quotes are from Digiday's February 2026 analysis.

Criteo Commerce Media is strong on the retailer side with auction-based display launched June 2025, transparent measurement, and an early agentic AI integration (ChatGPT pilot 2026). Criteo's 2026 outlook frames the agentic shift bluntly: what happens when shoppers no longer type "back-to-school dorm supplies," and instead ask detailed preference-based questions (Criteo, November 2025). The benefit for retailers is cross-device targeting and AI-holistic optimization across the Criteo retail media network; the limit is that marketplace operator use cases (multi-seller self-serve, seller wallet, commission splits) are not Criteo's primary positioning.

CitrusAd/Epsilon under Publicis ownership leverages 300M+ CORE IDs for cookieless targeting and unified on/off-site retail media — a strong identity moat for enterprise retailers like Macy's, Lowe's, and Harris Teeter. Less suited to mid-market or marketplace use cases.

Mirakl Ads is the closest competitive analog to Osmosphere on the marketplace side. Native Mirakl marketplace integration, second-price auction, strong self-serve onboarding, and the proof points to back it: 258% advertising spend growth in 2025, close to 50 retailer clients, $14.6 billion in annual GMV across the platform up 31% year-over-year, and over 35 customers surpassing the $100 million GMV threshold in 2025. The trade-off is ecosystem lock-in: Mirakl Ads requires the Mirakl marketplace platform underneath. Operators who want a single retail media OS that serves both their marketplace seller activity and their first-party retailer brand campaigns will hit that boundary quickly.

Topsort is the API-first infrastructure option. Per Topsort's own positioning, "API-first integration means campaigns can launch in under four weeks without overhauling existing buying workflows" (Topsort, 2025). Strong server-side auction with first-price and second-price options, well-suited to B2B marketplaces. Less complete on demand generation, seller self-serve dashboards out-of-the-box, and managed services — operators get raw infrastructure and build the rest.

The market concentration context that frames every selection: Amazon and Walmart will capture more than 89% of incremental US retail media spending in 2026, leaving the remaining 200+ networks to share the remainder (eMarketer, H2 2025; Skai 2026). Independent platforms — Osmosphere, Criteo, CitrusAd, Mirakl Ads, Topsort — are the realistic options for non-mega-retailers who do not want their data flowing through Big Tech intermediaries.

The Marketplace Decision Framework: When and How to Launch

Marketplace retail media becomes economically defensible at scale, not at concept. The Mirakl 2025 cohort — over 35 marketplace customers surpassing the $100 million GMV threshold — is a usable empirical benchmark for when the seller flywheel and ad demand generation make platform investment worthwhile. Below that, marketplace operators are typically better off proving the seller-funded model on a thin layer (sponsored listings only) before investing in a full retail media OS.

The build-vs-buy choice is tactical, not strategic. Most marketplace operators outside the top-three globally do not have the engineering bandwidth to build a multi-seller auction, wallet, onboarding, and analytics stack from scratch — and big tech-adjacent platforms re-introduce the data ownership concern that running a marketplace was supposed to solve. For the extended argument see how to build a marketplace ad platform without Big Tech. The point here is that white-label platforms collapse build cycles dramatically — Osmos's Turnkey Solution offers full retail media OS launch in 4 weeks, and the API-first vendors (Topsort, Mirakl Ads) all advertise sub-month integration timelines.

Best practices for marketplace setup, drawn from Mirakl's 50-client cohort, Topsort's API-first deployments, and Osmos's BigBasket / Pick n Pay / Konvy work:

1. Start with seller activation tools, not media planning consoles. Self-serve onboarding (Onboard Pro-style flows) and a workable seller wallet beat a fancy bidding interface every time when sellers are the demand side.
2. Pick a second-price auction for sponsored listings. It is the dominant model for marketplaces because it controls advertiser overpaying and keeps small-seller participation viable.
3. Instrument incrementality from day one. Measurement fragmentation is the single largest pain point in 2026: 78% of brands flag measurement as the area most needing standardization (Skai 2026).
4. Pace seller spend. Wallet-based prepayments and credit lines protect both seller liquidity and the marketplace from advertiser default.
5. Plan ad formats around your category mix. Fashion marketplaces need shoppable video, story ads, and editorial placements; FMCG marketplaces need sponsored listings and display; B2B marketplaces lean on category-page sponsored placements.

For benchmark performance expectations after launch, see retail media ROI benchmarks for marketplaces — that sibling covers the post-launch ROAS and revenue-per-seller numbers in detail.

On technical implementation: marketplace retail media platforms are typically built around an auction service (real-time placement decisions), a campaigns API (advertiser configuration), an events API (impression and click logging), and a reporting API (analytics). Osmos's API Hub exposes these four primitives directly, with full launch timelines as short as two weeks for API-only integrations and four weeks for the complete Turnkey Solution. Implementation depth beyond conceptual architecture varies by vendor and by the marketplace's existing checkout, listings, and identity infrastructure — operators should expect any vendor evaluation to include a discovery phase mapping marketplace-side hooks before quoting a deployment timeline.

The Retailer Decision Framework: When and How to Launch

Retailer-direct retail media has a different economic gate. The threshold question is not GMV — it is whether the retailer has enough loyalty data, transaction volume, and category depth to make a brand advertiser proposition compelling. Walmart, Kroger, Target, Tesco, and Albertsons cleared that bar years ago. Mid-sized regional grocers, specialty retailers, and DTC-leaning chains often need a partner platform to bring the identity layer they do not own.

The best-practice setup follows a five-step pattern that repeats across the retailer cohort:

1. Data audit. Map first-party customer data: loyalty, POS, online behavior, app usage. Assess identity coverage and clean-room readiness.
2. CDP or composable data layer. Stand up the unified shopper record. This is where most retailer retail media programs stall.
3. PDP and onsite optimization. Sponsored listing inventory, display placements, and category-page real estate need to be defined and instrumented.
4. Network launch with a short advertiser shortlist. Start with three to ten endemic CPG or category brands. Avoid simultaneous full-roster onboarding.
5. Incrementality measurement. Per Skai 2026, 54% of brands measuring incrementality reduced wasted spend and 49% increased new customer acquisition. Treat incrementality as a launch deliverable, not a Year-Two project.

Common retailer challenges to plan around: 78% of brands flag measurement standardization as the area most needing improvement (Skai 2026), advertiser demand generation is harder for retailers without Amazon's or Walmart's scale, walled garden data silos limit cross-network attribution, and over-engineering the platform before proving demand is the most common waste pattern. The IAB Europe Commerce Media Measurement Standards V2 (transition window through end of July 2026) gives retailers a credible standards baseline to build measurement against.

For retailers that want speed-to-launch over multi-quarter build, Osmos's omnichannel retail media platform covers on-site, off-site, and in-store in a single stack with a 72-hour go-live for the omnichannel components and a 4-week full deployment for the complete platform. The white-label model means the retailer remains the data controller — no shared infrastructure with Amazon or Walmart, no Publicis agency bundle, no ecosystem lock-in.

Strategic Considerations and Common Mistakes

Six selection mistakes recur across both marketplace and retailer programs:

Choosing a marketplace-optimized platform when you are a retailer (and vice versa). Marketplace platforms typically lack first-party data activation and brand-advertiser portal depth; retailer platforms typically lack seller self-serve, wallet management, and multi-tenant architecture. The mismatch is invisible at procurement and obvious six months in.

Over-engineering before proving demand. Operators routinely commission elaborate stacks before validating that endemic advertisers will actually buy. Topsort's "under four weeks" framing and Osmos's Turnkey Solution exist to compress this risk by getting a thin platform live and observing real demand signals before scaling.

Underestimating data ownership traps. Big Tech-adjacent platforms — Amazon Retail Ad Service, large agency-bundled stacks — often place the operator's customer data inside structures the operator does not fully control. Clean rooms are technical separations, not structural ones. White-label deployments solve the structural problem.

Pricing model misalignment. Marketplace seller advertisers respond to CPC sponsored listings; brand advertisers buying display or CTV expect CPM; premium tenancy is fixed-fee. A platform that supports only one pricing model forces inventory choices that limit revenue. Osmosphere supports CPC, CPM, fixed tenancy, and hybrid models on the same stack.

Ignoring measurement fragmentation. Three-quarters of brands report measurement capabilities are still weak or just adequate (Skai 2026). Operators who launch retail media without a measurement plan compatible with IAB Europe V2 standards or comparable frameworks set up their own renewal-cycle credibility problem.

Treating retail media as a side revenue stream. When advertising is 31% of Flipkart's overall revenues (Storyboard18), that is not a side bet. Operators that invest accordingly — dedicated team, dedicated platform, dedicated measurement — capture the upside. Operators that under-invest end up ceding the category to whoever does.

For the future-state version of this argument — retailers becoming media networks in their own right — see the sibling spoke on the future of retail media and retailers becoming media networks. For 2026 the practical gates are the ones above.

Frequently Asked Questions

What Are Amazon Advertising Pricing Models?

Amazon Advertising operates on three distinct pricing models. Sponsored Products is CPC (cost-per-click), self-serve, with no formal minimum spend — the entry-level option for marketplace sellers. Amazon DSP managed service requires a minimum of $50,000 USD per month and operates on a CPM basis; CPM rates vary by inventory type, targeting, and competition. Amazon DSP self-service has no formal minimum spend (MediaPlanningTool, 2026). Sponsored Display sits in between, offering both CPC and CPM options.

What Is the Difference Between Amazon Retail Media and Amazon DSP?

Amazon Retail Media (Sponsored Products, Sponsored Brands, Sponsored Display) runs primarily on a CPC self-serve model on Amazon-owned surfaces, focused on lower-funnel conversion. Amazon DSP runs on a CPM model — managed service ($50K/month minimum) or self-serve — and reaches off-Amazon inventory including Streaming TV (with Spotify, Netflix, Disney, and Roku partnerships expanded in 2025), audio, and third-party display via Amazon Marketing Cloud (AMC) for clean-room measurement. Amazon's Unified Campaign Manager (announced at unBoxed 2025) bridges both for advertisers running cross-format programs.

Amazon vs Walmart Connect: Which Retail Media Network Wins in 2026?

Amazon dominates by scale: $68 billion in 2025 advertising revenue versus Walmart's $6.4 billion global ad business (Digiday, February 2026). But Walmart Connect has the higher growth rate (41% in Q4 2025) and the more aggressive 2026 strategic posture — Vizio CTV creating omnichannel closed-loop measurement and AI partnerships with ChatGPT, Gemini, Meta, and TikTok. For US-centric retailers and brands focused on grocery and general merchandise, Walmart Connect's omnichannel proposition is increasingly the more interesting bet. For pure-play scale and ad tech depth, Amazon remains the default.

What Are the Benefits of Amazon DSP for Retailers?

Amazon DSP gives retailers off-Amazon programmatic reach (premium streaming with Spotify, Netflix, Disney, and Roku partnerships expanded in 2025), custom audience construction against Amazon's shopper signals, Streaming TV inventory at scale, and Performance+ AI optimization. Amazon Marketing Cloud (AMC) provides clean-room measurement for closed-loop attribution. The trade-off is the $50K/month managed service minimum and CPM-based pricing, which narrows DSP's economic fit to brands with sustained programmatic budgets — and the AWS data architecture that surrounds the Retail Ad Service offering.

Sources

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2. eMarketer (H2 2025). Retail Media Ad Spending Forecast and Trends H2 2025.
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5. Criteo (November 2025). What's Next for Retail Media: A 2026 Outlook.
6. Mirakl (February 2026). Mirakl 2025 Key Results: $218M ARR, $14.6B GMV, Launch of Mirakl Nexus.
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8. Walmart Corporate (March 2026). Walmart and VIZIO Scale Content to Commerce at IAB NewFronts 2026.
9. Zalando Corporate (July 2025). ZMS Turns 10: How Zalando's Retail Media Unit Helps Fashion and Lifestyle Brands.
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12. Storyboard18 (September 2025). Flipkart's Ad Income Jumps 27% to Rs 6,317 Crore in FY25.
13. Topsort (2025). 2025 Guide to Demand-Side Retail Media Platforms — What to Look For.
14. MediaPlanningTool (2026). Amazon DSP Review 2026: Is the $50K Minimum Worth It?.
15. Digiday (February 2026). Walmart Connect's Full-Funnel Ambitions Come Into Focus, With Amazon in Its Sights.