Programmatic DOOH, explained

Programmatic DOOH buys digital out-of-home through automated platforms against an audience and conditions rather than by booking named sites. There is no cookie and no click, so targeting happens at the level of place and time, and one purchased play is counted as many impressions. It buys flexibility and trades away certainty about which screens ran your brand.

Programmatic arrived in out-of-home about a decade after it reshaped display, and it arrived changed, because the thing it was designed for does not exist here. There is no individual. A screen shows an ad to everyone in front of it, whoever they are. The IAB's own definition of digital out-of-home, published in December 2024, lists programmatic buying as something DOOH can support, "while not a core requirement."

Understanding what survived that translation is most of understanding pDOOH.

How does the supply chain fit together?

Advertiser / agency
        │  sets audience, geography, budget, rules
        ▼
  DSP  (demand side)
        │  bids for screen time
        ▼
  SSP  (supply side)
        │  aggregates and exposes inventory
        ▼
Media owners and format operators
        │
        ▼
     Screens
  

The demand-side platform is where a buyer works. The supply-side platform is where owners make inventory available. Between them sits an auction, or more often a deal, for slots in a screen's loop. Each layer takes a share of the spend, which is the honest argument for buying direct when you already know exactly which screens you want. The layers are the same ones described in the guide to out-of-home advertising; programmatic only changes how the middle two talk to each other.

Who sits where in the programmatic DOOH stack?

Named platforms, each described from its own published material, in alphabetical order within each side. This is a role map, not a ranking. Digital formats were 36.3% of US out-of-home revenue in 2025 by OAAA's count, and the share of that bought through these systems is not published in a form that can be cited.

Two things to notice. The same company can be on both sides of a transaction: Vistar Media by design, Hivestack by product line, Broadsign after buying a DSP in 2024 and an SSP in 2025. When a platform tells you it is neutral, ask which product it is being neutral with.

The other is that moving inventory already has a supply-side answer. Place Exchange's November 2022 launch of geospatial ad units put it plainly: until then, mobility media owners had to assign a single fixed location to each vehicle as if it were stationary. The mobility partners named at that launch were Curb, Firefly, Lyft Halo, Octopus, Road Runner Media and Uber OOH. Firefly is the worked example of a mobility operator that can be bought this way: its own solutions page lists Place Exchange, Vistar Media, Hivestack and Broadsign as the SSPs carrying its digital tops, with programmatic guaranteed or open-marketplace deals and dynamic creative, and an April 2026 announcement added VIOOH. Both pages are in the sources.

What can you target without cookies?

Not people. Conditions. Which turns out to cover more than it sounds:

Triggers are the genuinely distinctive capability. A direct booking cannot start a campaign the moment it rains and stop when it clears.

What you cannot do, and what a display planner will keep reaching for out of habit:

• Target a person. There is no identifier in the request for the people in front of the screen.
• Cap frequency per person. Caps apply to the screen and the loop, not to the viewer.
• Optimise to a click or a conversion pixel. Nothing is clicked. Optimisation works on delivery conditions.
• Build a lookalike from site visitors. The audience is a modelled count of passers-by, not a list.
• Retarget the viewer directly. Some DSPs offer retargeting of devices observed near a screen during a play. That is a device-location product with its own permission and data-broker questions, covered on location-based advertising.

What is the difference between open exchange, private marketplace and programmatic guaranteed?

Four ways of transacting, and the OpenRTB 2.6 specification describes each of them in the bid request itself. The table uses the specification's own field names so a planner can ask a platform which one a proposal is.

A real example of the split. Display & Video 360's DOOH documentation describes inventory arriving either as a deal negotiated offline with a seller and then imported by deal ID, or through its Marketplace, and it supports both guaranteed and non-guaranteed deal types. On the sell side, VIOOH's trading manager describes the same two families: programmatic guaranteed, and non-guaranteed deals with no upfront commitment that let a buyer shift budget in flight. Out-of-home tends toward deals rather than open auction because owners think in packs of screens and posting periods, and a deal is the programmatic shape of a pack.

How does a deal ID actually work?

1. The owner packages screens. A set of screens, a period, a floor, and optionally an allowed list of buyer seats or advertiser domains.
2. The SSP issues the deal. In OpenRTB terms a Deal object with a required id, a bidfloor, an optional auction-type override and a guaranteed flag.
3. The buyer enters the id in the DSP. From then on, every bid request for those screens carries the deal inside a Pmp object; if the owner set private_auction to 1, bids outside the named deals are ignored.
4. The DSP bids with the same id. The bid response carries a dealid that references the deal in the request.
5. The seller checks conformance. IAB Tech Lab's auction primer notes that sellers may validate that bids carrying deal IDs conform to the deal's terms before the bid enters the auction.

Three questions to ask about any deal you are handed: which screens are actually inside it; whether it is guaranteed or merely preferred; and where the impression multiplier on those screens comes from, since the specification lets the source be the publisher or a named measurement vendor.

Functional comparison: programmatic buying on DOOH vs display

The mechanics look identical from inside a DSP, which is the problem. Row by row, they are not.

The multiplier row is the one to internalise. IAB Tech Lab's note on integrating DOOH into OpenRTB spells out that one ad play equals multiple viewers, that the number is a statistical estimate, and that fractional values such as 0.32 impressions per play are common. A display CPM and a DOOH CPM are not the same unit until you know the multiplier and who produced it.

What does programmatic buy you?

• Reach across owners. One buy spanning suppliers who would each need a separate negotiation.
• Mid-flight change. Budget, geography and creative can move after launch.
• Short commitment. No four-week minimum tied to a production schedule.
• Conditional delivery. Rules a human booking process cannot execute.

What do you give up?

• Certainty about placement. You get delivery, not a guaranteed list of the sites your brand appeared on. For a brand with adjacency rules, that matters.
• Margin. Every intermediary takes a share of the media spend.
• Comparability. An audience number produced by a platform's model and one produced by a measurement body are not the same figure. Geopath defines an impression as the number of people passing a display who are likely to notice the ad; a seller-supplied multiplier may or may not have been built that way.

Where does programmatic quietly break?

On inventory that moves. The whole model assumes a screen has coordinates: that is how venue type is assigned, how audience indices are attached, and how delivery gets reported by location.

A screen on a vehicle has a route instead. It can be sold programmatically, and it is, but the location-derived attributes in the system have to come from somewhere. If nobody says where, the buyer is reading a number whose geography was assumed rather than measured. Ask. The reasoning is on how out-of-home impressions are measured.

That is not a hypothetical corner of the market. Screen-based inventory on vehicles is sold programmatically today, Firefly's digital tops through five SSPs by its own count, and none of it has a fixed coordinate. The geospatial unit described above is the supply side's admission of the same point: the sellable thing is the place the screen passes through, not the screen.

When should you use it?

1. Use programmatic when you want an audience across several markets, need to change things mid-flight, or have a condition that should govern delivery.
2. Buy direct when specific locations are the point, when adjacency matters, or when you want the best terms on one site.
3. Do both on larger plans: direct for the sites that must be covered, programmatic for reach around them.

Where to go next

What DOOH is covers the format itself, and how the market is structured explains which kind of company sits at each layer of that supply chain, including the specialists who run the screens that move. The operators and platforms themselves, with which SSPs each names for its inventory, are on DOOH companies.