Disputing the ‘Dumb Pipes’ Theory: The Evolution of SSPs

“SSPs are dumb pipes” has been the pitch behind every direct DSP-to-publisher initiative for the last three years. The evidence from 2026 suggests the pipes were doing more than routing bids, and the buyers who cut them out found that out the hard way.

The “dumb pipes” argument is simple and has real intuitive appeal: supply-side platforms sit between publishers and demand, take a cut, and add technical routing but not much else. Cut them out, connect DSPs directly to publisher inventory, and everyone keeps more of the media dollar. It’s a clean story. Whether it survives contact with how direct connections have actually performed is a separate question.

What the “dumb pipes” theory actually argues

The strongest version of the argument, championed loudest by DSPs building direct publisher products, is that SSP value has eroded to almost nothing beyond basic auction routing. Curation, brand safety screening, and supply path optimisation, the argument goes, can all be replicated or improved by the DSP itself, with the SSP’s take rate becoming pure overhead once that replication happens. It’s not a baseless argument. Some SSP margin genuinely is closer to toll-collection than value-add, and buyers have real reason to want that margin exposed.

The OpenPath test case

The Trade Desk’s OpenPath, its direct publisher-buying product, was the highest-profile real-world test of this theory. Adoption grew meaningfully through 2025, reportedly reaching around 10% of The Trade Desk’s revenue by Q3 FY2025, with major CTV publishers onboarded directly. Then, in February 2026, Adweek confirmed that both Dentsu and WPP had quietly exited OpenPath, citing a lack of transparency into where spend actually landed and undisclosed fees, the exact complaint the “dumb pipes” theory promised direct connections would eliminate. Other buyers had pulled back earlier for the same reason. Removing the SSP didn’t remove the opacity. It just changed who was responsible for it.

What an SSP is actually doing, when it’s doing its job

The honest version of SSP value isn’t romantic, but it’s real: curated deal management, supply path optimisation across multiple demand sources rather than one, fraud and brand safety screening at scale, and, when done well, a layer of accountability the publisher can point to if something goes wrong. None of this is unreplaceable in principle. All of it takes real infrastructure and ongoing investment to replicate well, which is exactly the cost DSPs building direct paths are discovering once they try to do it themselves rather than just remove a line item.

There’s a version of the “dumb pipes” argument worth taking more seriously than the strongest version: not every SSP relationship justifies its fee, and some genuinely do function as closer to a toll booth than a value-add service. The mistake isn’t believing that some intermediation is unnecessary. It’s assuming all intermediation is unnecessary, and that removing the label “SSP” from a transaction automatically removes the underlying costs that label was covering.

What this means for supply path decisions now

The lesson isn’t “SSPs are always worth their fee” any more than the original theory was “SSPs are never worth their fee.” It’s that removing an intermediary doesn’t automatically remove the problem the intermediary was, imperfectly, managing, transparency, curation, accountability. The same due-diligence questions that matter for evaluating any SSP relationship, covered in Unraveling the SaaS Proposals of Magnite and PubMatic, apply just as directly to a DSP’s own direct-connection product. The label on the intermediary changed. The questions worth asking about it didn’t.