TL;DR: Verification vendors have historically measured whether an impression was delivered in a viewable, brand-safe context. As bilateral deal records become more common, the measurement question extends: was the impression delivered in accordance with the terms agreed in the DealSheet? This is a different product from viewability measurement, but it builds on the same infrastructure of independent third-party access to delivery data. Verification vendors are moving into this space because it is adjacent to their existing capability and because the market for deal record auditing is growing faster than the market for conventional delivery measurement.
The independent verification market grew from a specific problem: buyers and sellers in programmatic advertising held separate delivery records that frequently disagreed, and there was no independent party who could adjudicate. Verification vendors, connected to both buy-side and sell-side ad servers, filled that role. They became the reference standard for viewability and brand safety measurement because they occupied an independent position in the ad serving chain that neither party could.
The same structural dynamic is now emerging around deal records. As bilateral deal infrastructure becomes more common, the question of independent verification extends from "was this impression delivered in a brand-safe, viewable context?" to "was this impression delivered on the terms agreed in the DealSheet?" The second question requires access to the DealSheet as well as to the delivery data, and it requires an independent party who can compare the two.
What deal record auditing involves
Deal record auditing involves three components that verification vendors are well positioned to provide.
The first is DealSheet access. An independent auditor needs to access the DealSheet data to perform the audit: the agreed CPM, the inventory specification, the audience parameters, and the delivery terms. In a bilateral deal infrastructure where both parties hold the same document, an independent third party with access to the marketplace's DealSheet API can retrieve this data without either party providing it. The independence is structural, not dependent on the parties' cooperation.
The second is delivery data matching. The auditor compares the delivery data (impressions served, CPMs charged, inventory sources, audience segments) against the DealSheet terms. Discrepancies between the agreed terms and the delivery data are the audit findings: they may represent delivery shortfalls, CPM overcharges, or inventory substitutions.
The third is mandate compliance checking. For buyers with formally documented mandates, the audit can extend beyond DealSheet compliance to mandate compliance: were the deals agreed within the mandate parameters? This requires access to the mandate document, which the buyer provides, and the DealSheet, which the marketplace provides. The auditor can then confirm that the agent's decisions were within mandate and that the deals were executed on the agreed terms.
Why verification vendors are expanding into this space
Verification vendors have three structural advantages in deal record auditing.
Independent position. They are already recognised as independent third parties in the programmatic supply chain. Buyers and publishers are accustomed to providing them with access to delivery data. Extending that access to DealSheet data is an incremental change in the relationship.
Existing measurement infrastructure. The data pipelines, matching systems, and reporting platforms that verification vendors have built for delivery measurement can be extended to deal record data without fundamental architectural changes.
Growing buyer demand. As programmatic buyers deploy more bilateral deals and agentic mandates, the question of independent audit is becoming a client and finance requirement rather than an optional best practice. Buyers who are committing significant budgets to bilateral channels need to be able to demonstrate to their own organisations that the deals executed were within mandate and delivered on the agreed terms. An independent audit from a verification vendor is a more defensible evidence base than a self-audit.
What this means for the verification market
The expansion of verification vendors into deal record auditing is changing the competitive landscape for measurement in programmatic advertising.
Vendors that have invested in DealSheet API integrations and mandate compliance checking are building a new product line adjacent to their existing measurement suite. For clients running significant bilateral programmes, this becomes a bundled offering: viewability and brand safety measurement alongside deal record and mandate compliance auditing.
The MRC's working standards for agentic measurement, published for comment in 2026, are expected to include accreditation requirements for deal record access and audit methodology. Vendors who have built deal record auditing capability before those standards are finalised will have an accreditation advantage over those who build reactively.
For buyers evaluating their verification vendor relationships, the question is whether their current vendor has deal record auditing capability or has it on a credible near-term roadmap. The demand for this capability will grow as bilateral buying scales, and the buyers who have the right vendor relationships in place before the demand peaks will be better positioned than those who build them under pressure.