Switching Retail Media Platforms: Osmos's Migration Checklist Before You Move

Last updated: October 2026. Reviewed by Kunal Damgude, Growth and Product Marketing Manager.

A retailer switching retail media platforms has to move each advertiser's tier, wallet balance, billing terms and contract commitments; its live, paused and completed campaigns with their approved creative; its reporting history and the benchmarks built on it; and its approval workflows and ad policy reviews. It then tests the migration before the full cutover: it runs both platforms side by side until spend, delivery and reporting match, and moves a pilot group of advertisers ahead of the rest. A move onto Osmos takes four weeks on average.

Osmos is a white-label retail media operating system for retailers and marketplaces. Its modular apps for onsite, offsite and in-store ads sit over your existing stack, so you can break your monetisation ceiling faster without rebuilding it.

Every check assumes the retailer has already chosen the platform it is moving to. Ad Tech Infrastructure: Building the Engine Behind Retail Media sets out how the parts of a retail media ad stack fit together, from the ad server and auction to reporting and integrations. The build versus buy analysis works through the earlier decision on whether to build a platform in-house or license one.

1. Advertiser data and commercial terms

Advertiser records and the commercial terms attached to them move first, because every campaign, invoice and report on the new platform is built on them. Each wave of advertisers has its own cutover: the moment its campaigns, balances and billing move. The full cutover is the last wave.

Advertiser profiles, tiering and segmentation rules

When tiers carry over intact, a Tier 1 advertiser is recognized as Tier 1 on its first day on the new platform, with the same account manager, negotiated rates, access to reserved inventory and service level it had the day before. The rules that decide who sits where are often split between the old platform's settings, the customer relationship management (CRM) system and the memory of the sales team.

• Record each advertiser's legal and billing entity, the brands and sub-brands it advertises, and any agency that buys media on its behalf.
• Note the tier each advertiser sits in today and the rule that put it there, such as a spend threshold, a category or a named strategic account.
• Write down what each tier entitles an advertiser to, including service level, pricing, inventory access, credit terms and reporting.
• Export the user accounts and permissions each advertiser's team holds on the old platform.

Map each tier to the new platform's configuration, deciding the mapping yourself where the two platforms segment advertisers differently, and check the largest accounts by hand before cutover. If the mapping is skipped, the new platform applies its default setting to everyone, often the self-serve one, and a brand that has spent heavily for years starts out as an unknown account.

Wallet balances, prepaid credits, and MDF or incentive commitments

An advertiser wallet is a prepaid balance held against an advertiser's account, which campaign spend draws down. Market development funds (MDF) are marketing budgets a brand commits in advance for agreed activity, and where they fund retail media they can sit against the brand's account in the same way. Incentives are credits the retailer grants, such as bonus media for a first campaign or for trying a new format.

Each kind of balance follows its own rules: cash top-ups belong to the advertiser, promotional credits may expire or apply to a single format, and MDF was committed for specific activity that the brand's trade marketing team will reconcile it against. Merging them into one number loses those rules, and a credit meant for video ads can end up paying for search ads.

When a balance is off, even by a small amount, the advertiser's finance team usually finds it before the retailer does. A balance left active on both platforms during the transition can be spent twice.

• Fix a cutover timestamp after which no top-up, spend or refund is recorded on the old platform.
• Export each balance by type at that timestamp, with its expiry date and conditions.
• Load the same balances on the new platform as opening positions, and have finance sign off that the two totals agree.
• Send every advertiser a statement showing its closing balance on the old platform and its opening balance on the new one.

On Osmos, the Wallets & Billing app keeps top-ups, credit lines, invoices and reconciliation in one ledger and runs promotion balances per campaign type, so a promotional credit stays separate from the advertiser's cash after the move.

Payment methods, invoicing history and billing cycles

Capture how each advertiser pays, whether by prepaid top-up, card, bank transfer, a credit line on agreed terms or invoicing through an agency, along with its billing entity, purchase order references, tax details, currency, agreed billing cycle and invoice format. An invoice in an unfamiliar format can fail an agency's purchase order matching and sit unpaid, and an unpaid invoice on a credit line, like an empty wallet, can pause a live campaign.

Card details stored by the old platform's payment provider may not move with the account, in which case advertisers who pay by card have to add the card again, and they should hear about it before their first charge on the new platform is due. Where possible, line up the cutover with the end of a billing cycle. A cutover in the middle of a month leaves two platforms each responsible for part of the period, with the risk of two invoices for one month or none at all.

Export the full invoicing history, including credit notes and adjustments, into the retailer's own finance system while the old platform is still accessible, because disputes and audits will ask for it long after the move.

Contract terms tied to the old platform

Minimum spend commitments, volume rebates and exclusivity clauses are written into the advertiser contract. The mechanism that tracks or enforces them often sits inside the old platform: the year-to-date spend counting toward a minimum, the rebate tier an advertiser has reached, and the rule that keeps a competitor off a category page during a brand's exclusive period. The new platform starts each of these from zero, so the positions have to be carried across. A missed position tends to surface at year end, when an advertiser that met its minimum spend across both platforms finds its rebate calculated on the new platform's spend alone.

• List every advertiser contract with a term that depends on the platform, and record its year-to-date position at cutover.
• Re-create exclusivity rules in the new platform's ad serving before any affected campaign moves.
• Amend contracts that name the old platform, or its reports, as the source of measurement.

Read the retailer's own contract with the outgoing platform the same way, for its notice period, any exclusivity, minimum fees and, above all, what data the retailer can take with it and in what format.

Exclusivity with a platform partner can also be reopened before it runs out. AdExchanger reported in August 2025 that Walmart and The Trade Desk had quietly renegotiated their 2021 arrangement the year before, adding a provision that allows Walmart to work with other ad platforms, and Advertising Week covered the same change in September 2025.

2. Campaigns and creative

Active campaigns: no gap and no duplicate charge at cutover

For each live campaign, capture the total and remaining budget, spend to date, flight dates, pacing, bids, targeting, placements, creative, frequency caps and any delivery guarantee.

• Let campaigns that end before their wave's cutover finish on the old platform, and move only long-running and always-on campaigns.
• Rebuild each moving campaign on the new platform with only its remaining budget.
• Stop each campaign on the old platform and start it on the new one at the same agreed time, and give a single platform the job of billing any overlap.
• Watch pacing closely for the first few days, because a new auction can spend faster or slower than the old one on the same settings.

Booked placements such as homepage takeovers and fixed tenancies also need their delivered impressions to date carried over, so the guarantee is measured across the whole flight. A fixed placement can also be booked twice while both systems take bookings. While both systems are live, Osmos's Inventory Studio keeps one record of what is booked, because its two-way state sync carries a booking made in a connected source system into Osmos and a booking made in Osmos back to the source system.

Paused campaigns: whether and how they resume

Each paused campaign was stopped for a reason: a seasonal campaign waiting for next year's holiday period, a campaign stopped because its product went out of stock, one paused when a wallet ran dry, or one held back until new creative arrives. For each paused campaign, record why it was paused, whether the advertiser expects to resume it, its remaining budget and the terms it was booked on, including price, bids and any promotional credit.

Agree with the advertiser whether it resumes on those original terms or on the new platform's terms, and archive campaigns that have been paused for a long time with no plan to return, so the new platform does not start with clutter.

Historical and completed campaigns

Keep completed campaigns where account and finance teams can reach them: imported into the new platform, read-only on the old one for a fixed period, or in the retailer's own data warehouse. Account teams need them for quarterly business reviews (QBRs) and renewal conversations, and finance needs them to answer a query on an old invoice.

Export them at the level of detail the QBRs use, typically daily results by campaign, placement and format with attributed sales, and keep the attribution settings that produced those results alongside them, so the numbers can be read the same way later. Complete the export while the contract still gives access, so the retailer holds its own record of what was delivered, whatever happens to the outgoing vendor's systems.

Creative assets and their approval history

For every creative asset, move the file, its specs, its approval status, who approved it and when, any conditions attached to the approval, such as the placements it is cleared for or an end date on a promotional claim, and its rejection history. Ads assembled automatically from the product listing carry over with the catalog feed and product data.

Compare the two platforms' ad specifications, including sizes, file types, file weight and safe areas, and identify before cutover which approved assets fall outside the new specs. Tell those advertisers what has to change and by when, and let every other asset keep its approval. Asking an advertiser to resubmit and re-approve its whole library moves the retailer's migration work onto the advertiser, often in the middle of its campaign calendar, and holds up campaigns that were approved long ago.

3. Analytics and reporting continuity

Historical performance data: backfill or a reporting gap

Backfilling means loading historical performance data into the new platform's reporting, so an advertiser who opens a dashboard after the move sees its past results next to the new ones. The retailer can backfill history into the new platform, keep it in its own data warehouse and join it to the new platform's data in a reporting layer, or accept a gap and give advertisers exports of their past results. Each approach can work if advertisers know in advance which one they are getting. Without that notice, an advertiser logs in after the move, finds nothing before the cutover date and concludes its history has been lost, which puts the migration at the center of its next renewal conversation.

Two platforms can count impressions, clicks and attributed sales differently. Label backfilled history with the definitions it was counted under, and load it only after live campaigns record correctly on the new platform, so a setup error shows up in current data first.

Benchmarks and year-on-year comparisons

Measure both years with the same definitions for every comparison that spans the move. The comparisons internal teams and advertisers use to set budgets and negotiate renewals include this year's peak season against last year's, return on ad spend (ROAS) by category, trends in cost per click and cost per thousand impressions (CPM), fill rate, and the category benchmarks a retailer shares with its advertisers.

Document the old platform's metric definitions before cutover: the attribution window, whether view-through conversions count, whether sales are counted at product or brand level, how an impression is defined, which time zone closes the day, the currency, and how returns are netted. Configure the new platform to match wherever it can. Adobe's guidance on moving from Adobe Analytics to Customer Journey Analytics makes the same point for analytics tools, noting that attribution settings have to be explicitly configured in the new tool to match historical reporting logic where continuity is required. When definitions change without notice, a shorter attribution window lowers the ROAS an advertiser sees at renewal time, and the retailer has to explain a drop that comes entirely from the change in counting.

Where the definitions differ, publish a bridge, either restated history or a documented adjustment that explains which numbers moved because of definitions. Mark the cutover date on every trend chart, and keep the old category benchmarks in use until the new platform has enough data to replace them.

The measurement standards advertisers trust need to carry over along with the numbers. After Rapido, the Indian ride-hailing platform, moved its retail media program from Google Ad Manager to Osmos, advertiser interest was strong but larger budgets were slow to follow, because advertisers wanted independent verification of impressions and viewability and measurement standards they already knew. Osmos enabled Integral Ad Science (IAS) verification and hourly reporting. Rapido reached a peak monthly ad revenue of $67K in January 2026, recorded a 41% MoM (month-on-month) increase in ad revenue, and saw $12K in incremental advertiser budgets move over from Google Ad Manager. The full case is in How Rapido removed advertiser budget migration friction with Osmos.

Dashboards and scheduled reports

Map every recurring report before cutover: leadership dashboards on ad revenue, fill rate and advertiser count, finance reports on billing and collections, the scheduled performance reports advertisers receive, and ad ops reports on pacing and exceptions. For each one, note who reads it, how often, which decisions depend on it, where its data comes from, and whether the new platform has a native equivalent that moves over or the report has to be rebuilt in a reporting tool on top of exports.

Rebuild them in order of use, and consider retiring the reports nobody opens. Amplitude's migration guidance recommends the same order: "Look at which dashboards and reports get the most engagement, migrate the data behind those first, and phase in the rest." Advertiser-facing schedules need particular care, because advertisers notice the first week a scheduled report fails to arrive.

4. Approval and governance

Creative and campaign approval workflows: who signs off

A written approval map lets the new platform enforce the same sign-offs from its first day. Set down who approves what today: which team checks a campaign's targeting and budget, which category managers approve brands on their pages, who signs off homepage placements, which campaigns above a budget threshold need senior approval, how quickly approvals are promised to advertisers, and where escalations go.

Then check whether the new platform can express the same hierarchy through roles, permissions, multi-step approval queues and approval rules by placement or category. Where it cannot, choose before cutover between changing the process and adding a manual step outside the platform. If the hierarchy is not rebuilt, campaigns either go live without a sign-off the category team expected or queue behind a single approver the new platform treats as the default. The move is also a reasonable moment to remove steps that existed only because of the old platform's limits, provided the teams who own those approvals agree. Where Osmos's Ad Ops as a Service team runs campaigns alongside the retailer's own team, the retailer decides where Osmos owns delivery and where its own team keeps control, and approval gates stay with the retailer.

Compliance and legal review for regulated categories

Many ad platforms treat categories such as alcohol, financial products and healthcare as restricted and put those ads through compliance review; X's published ads policies are one example. On a retail media network the same rules can be encoded in several places at once: category and keyword blocks, placement restrictions (keeping alcohol ads off baby and kids' category pages, for example), age gates, geographic limits, required disclaimers and a mandatory legal review queue.

List every such rule on the old platform, confirm each one exists on the new platform before any regulated campaign moves, and have legal sign off the list. A rule missed here can put a restricted ad in front of the wrong audience in the first days after cutover, and the retailer, as the publisher of that ad, carries the exposure. Carry over the documents regulated advertisers have already provided, such as licenses and claim substantiation, together with their approval records. With the rules and the documents in place before cutover, regulated advertisers keep running through the move without a fresh legal review of every campaign.

Internal SOPs and training material

Collect every document that references the old platform's interface, field names or workflows: standard operating procedures (SOPs) and runbooks, onboarding decks for new hires, screenshots in the team wiki, finance procedures, and the help articles advertisers use to upload creative or top up a wallet.

Rewrite each one for the new platform before cutover, retire the old versions so nobody follows them by mistake, and keep a short glossary that maps old terms to new ones for the first few months. Train ad ops, account management, finance and category teams early enough that they use the new platform during the parallel run. Give self-serve advertisers new guides, with a walkthrough session for the larger ones, because advertisers following outdated help pages fill the support queue in the weeks after cutover.

5. Testing and rollout

A parallel run with both platforms side by side

A parallel run is a period in which the old and new platforms both serve live campaigns, so spend, delivery and reporting can be compared on real traffic, and any discrepancy traced and fixed, before the old platform is switched off. The retailer pays for and operates both platforms until the parallel run ends.

Running the same campaign in full on both platforms would spend its budget twice, so the traffic, and each campaign's budget with it, has to be divided by placement, by share of traffic or by advertiser. The new platform can also run in shadow mode first, making ad decisions on mirrored requests without serving them, so auction and pacing behavior can be compared before any money moves.

• Agree before the run starts what each measure is compared against (such as the old platform on a comparable traffic share), what counts as a match for spend, delivery, attributed sales and invoiced amounts, and how large a difference is acceptable.
• Run for at least one full billing cycle, so invoices can be compared as well as dashboards.
• Name who signs off each measure, with finance on billing, analytics on reporting and ad ops on delivery.

A pilot group of advertisers before the full cutover

A pilot group is a small set of advertisers who move to the new platform first, so every part of the checklist is tested on real accounts before the full cutover. Choose the group to cover the range: one or two managed Tier 1 advertisers with strong relationships who agree to take part, several self-serve advertisers, at least one agency, a mix of ad formats, and an advertiser in a regulated category if the network carries one.

Tell pilot advertisers exactly what changes for them, what support they will get and how to report a problem, and run the pilot until each pilot advertiser has been invoiced on the new platform and has paid at least once. After the pilot, move the rest of the advertiser base in waves, by tier or by category, fixing what each wave finds before the next one moves, so a problem and the support work it creates reach one wave at a time.

Frequently asked questions

How long does a retail media platform migration take?

On Osmos, a migration takes four weeks on average. The timeline depends on the notice period and data export terms in the outgoing platform's contract, the length of the parallel run, and how many waves the advertiser base moves in after the pilot. Plan the full cutover away from the weeks before the retailer's biggest trading periods, when advertiser budgets are highest and an error costs the most.

What changes if the current platform is being shut down?

The outgoing vendor's wind-down date sets the deadline, so data exports move to the front of the plan: historical campaign data, invoices, balances and approval records all have to leave before access ends. The parallel run may be short or impossible, which makes the pilot group the main test. The choice of the next platform stays with the retailer, even when the outgoing vendor recommends one; Digiday's reporting on PromoteIQ, Microsoft's retail media business, noted that its customers were being introduced to a suggested platform and could decide whether to work with it.

What does it cost to switch retail media platforms?

Apart from the license fee or revenue share for the new platform, which the build versus buy analysis compares, a migration has costs of its own, and several of them run only while both systems are live: the outgoing platform's fees for the overlap, ad ops time spent running campaigns on two platforms, finance time reconciling two sets of wallets and invoices, engineering work to connect the catalog, conversion events and billing to the new platform, and any credits offered to advertisers to ease the move. Ad ops time is often the hardest to find, because the team keeps the old platform running at full load throughout. Osmos's Ad Ops as a Service team can take part of that load: it picks up live campaigns within two weeks of onboarding, with handover documentation and a baseline performance audit.

Who runs the migration project, and who decides the cutover date?

One person should own it end to end, usually the head of retail media or the ad ops lead, with the authority to set the cutover date and to postpone it if the parallel run does not reconcile. Under that owner, each group of the checklist needs a named lead: account management for advertiser records, finance for wallets, billing and contract positions, legal for contracts and ad policy, analytics for reporting, and ad ops for campaigns, creative and approvals. Account management should also own communication, so each advertiser hears about the move from the person it already deals with before it sees any change on the platform.

Does the checklist change when the retailer is moving off an in-house ad stack?

The same checks apply, and the commercial terms and the reporting take longer. A homegrown stack often keeps advertiser tiers, rebates and exclusivity rules in spreadsheets, custom code and the team's memory, so the commercial terms have to be written down from scratch before anything can move. Its metric definitions are often undocumented as well, which makes the year-on-year bridge harder to build. The wider trade-offs of running retail media on an in-house stack are covered in How to Build a Scalable Ad Tech Stack Without Third-Party Lock-In.

Does the checklist apply to a marketplace whose advertisers are third-party sellers?

Yes. On a marketplace the advertisers are often large numbers of third-party sellers, many of them self-serve, so tier mapping and advertiser communication have to work in bulk, through account-level updates and in-product messages. Where sellers pay for ads from their marketplace balance or through deductions from their payouts, the billing check also has to cover how those deductions will appear in seller settlements after the move. How the technology behind a marketplace's retail media network fits together is covered in the ad tech infrastructure guide.

Sources

1. AdExchanger, Daily News Roundup, 15 August 2025. adexchanger.com
2. Advertising Week, "Walmart's Trade Desk Split: Why It Matters For Retail Media", 15 September 2025. advertisingweek.com
3. Amplitude, "Migrating Analytics Platforms Without The Chaos", 22 June 2026. amplitude.com/blog/navigating-complex-migrations-for-success
4. Adobe Experience League, "Migrating from Adobe Analytics to Customer Journey Analytics". experienceleague.adobe.com/en/perspectives/migrating-from-adobe-analytics-to-customer-journey-analytics
5. X, Ads policies. business.x.com/en/help/ads-policies (verified 23 September 2026)
6. Digiday, "Microsoft looks set to shutter its retail media business", 7 October 2024. digiday.com