The Universal Ads API

Introducing AdCP: an open standard for agentic advertising

Every major social media company has an ads API, where anybody - small business or large agency - can log in and buy advertising. (Of course, these APIs have self-service interfaces on top of them, but let’s consider those “human APIs” for the purposes of this discussion!)

These APIs are native: they’re built for the formats that best fit the underlying content. They are built for outcomes: they generally have pricing, targeting, optimization, and workflows that help advertisers achieve something tangible. And they’re open: any advertiser can set up an account and buy ads, assuming they get through some policy checks.

We in the ad tech industry like to say that these social platforms are walled gardens because they won’t let us run programmatic auctions and third-party creatives on their inventory. This fight for “openness” is universal: why won’t Apple let me side-load apps on my iPhone? Why won’t Netflix put its content on my local cable network?

I think if companies want to invest an immense amount of care and money to make it as easy as possible to get great results from their product, that’s fantastic. As an Apple fanboy for almost 40 years, I learned about kerning while my PC friends were trying to figure out which side of the mouse pointed up. You go mess with Google Ads; I’ll just click “Boost” on my YouTube video and watch the views roll in.

Why doesn’t every publisher have an ads API that helps advertisers take full advantage of their unique capabilities?

Actually, most do: it’s a salesperson who spends countless hours inside of agencies, educating media buyers and planners, tied to a media buying process that could still be performed using fax machines.

Of course, the human API is expensive and doesn’t scale. Why not expose a real API and ad buying platform? Many, many have tried - for instance Vox’s Concert ad manager - but they require agencies to learn new tools or to find scarce technical resources to plug in. There are third party solutions, whether sell-side like DanAds or buy-side like Smartly, but these demonstrate the exact problem: Smartly - whose entire purpose is to integrate with ads APIs - only supports eight platforms.

Introducing the Ad Context Protocol

It seems impossible to have an ads API that is standardized and native. Programmatic standardized buying ads by commoditizing inventory, reducing ads to their lowest common denominator. Social made ads fully native, but there’s no standardized way to buy them.

But then Model Context Protocol (MCP) changed everything. In simple terms, MCP is a self-describing API. You (or your agent) can ask an MCP server: “so what can you do” and it will tell you.

This solves half of the standardized native problem: we can ask every publisher and platform what their ads API can do. The job of the publisher is no longer to build a media kit with fancy powerpoint slides; the job of the publisher is to make an API that lets an advertiser drive outcomes using their native capabilities.

The other half of the problem is that buyers still need to make sense of all of the different capabilities, make some decisions, and buy the ads. To do this, we need to layer some advertising primitives on top of the MCP protocol so that the back and forth process between the buyer (agent) and the seller (agent) is the same every time.

These standardized primitives to generalize and standardize the ad buying process are the Ad Context Protocol, or AdCP:

• Get Products: What ad products can I buy from you? What pricing models and currencies do you support?

• Create Media Buy: I want to buy some of the ad products you showed me (also update media buy to make changes)

• Sync Creatives: I have some creative assets that I want to share with you that you can use for my ads (potentially generating the actual creative as appropriate)

• Get Media Buy Delivery: I want to get reporting on how my media buys are doing

• Provide Performance Feedback: I want to tell you how my media buys are working so you can optimize for my actual goals

For creatives, there are three primitives:

• List Creative Formats: What formats do you support? What assets do they need?

• Preview Creative: Show me how my creatives will look in various contexts

• Build Creative: Make me a creative based on my brand guidelines, product catalog, and other assets

Companies can access and activate their own data through prompts:

• Get Signals: What data (contextual, audience, algorithmic) do you have for my objectives?

• Activate Signals: Make this data available on the platform(s) I want to buy on

These primitives work for traditional and digital ads. They work for ads in chatbots and ads on refrigerators. They are open to big agencies and small businesses; to big media and little creators. They are cost-effective and carbon-efficient. They create space for humans (nobody said this had to be a real-time API!) and for AI agents (because “just works” is a lot of work).

Available soon in an ad platform near you

For the past two months, more than 20 companies have been collaborating to build the first version of AdCP. It feels to me very similar to the early days of programmatic, when entrepreneurs were building foundational companies that today are household names. What’s different this time is that it’s not just startups: some of the largest publishers, platforms, agencies, and marketers are actively involved and helping to move agentic advertising forward.

As the first pilots launch over the next few weeks, we will all be learning together. The protocol will evolve to support more use cases. A new Lumascape for agentic advertising will emerge. There will be acronyms. There will be problems that we haven’t thought about. Skeptics will come out of the woodwork. Companies will defend their legacy programmatic business models.

My prediction, however, is that agentic advertising is too big, too important, and too obvious not to become the dominant paradigm. No advertiser wants to be limited to 8 platforms. No advertiser wants to buy commoditized ads priced for volume. No advertiser wants to pay for the costs and overhead associated with direct sales or programmatic ad tech.

Agentic advertising - powered by AdCP - will give advertisers what they want: open, efficient access to content-native advertising that drives outcomes.