Published: 17 September 2026

TL;DR: AdCP (Ad Context Protocol) is an open protocol published by AgenticAdvertising.org, separate from IAB Tech Lab's AAMP framework. It defines tasks that agents carry out across a campaign, from inventory discovery and media buys to creative, signals and delivery reporting. Alkimi is a marketplace: it provides a neutral venue where agents built to open standards can transact between buyers and publishers who may not have worked together before, working within IAB Tech Lab's AAMP framework. They are not competing: they sit at different layers. A buyer needs an agent built to an open agentic standard, such as IAB Tech Lab's AAMP or AdCP, to work with sell-side agents without a bespoke integration for each one. They also need a credible, neutral place to do the deal, which is what Alkimi provides.

The distinction between a protocol standard and a marketplace platform is not always obvious in advertising technology. OpenRTB is a protocol. DoubleClick was an ad server. The two coexist: the protocol defines how systems communicate; the platform provides the infrastructure where that communication happens. The same distinction applies to AdCP and Alkimi: AdCP is a protocol, Alkimi is a marketplace, and Alkimi itself works within IAB Tech Lab's AAMP framework.

What AdCP Is

AdCP (Ad Context Protocol) is an open protocol published by AgenticAdvertising.org, at version 3.2 as of October 2026. It is separate from IAB Tech Lab's AAMP (Agentic Advertising Management Protocols), an open-source framework that extends existing standards for agents through components such as agentic-direct, OpenProposal and reference buyer and seller agents. AdCP is a task protocol that runs over MCP or A2A, and its tasks span the campaign:

Inventory discovery and media buys. How a buy-side agent finds the inventory a seller offers and places a media buy against it.

Creative and signals. Tasks for handling creative and for working with signals as part of the campaign.

Governance checks. Tasks for checking a buy against the governance rules that apply to it.

Delivery reporting. Tasks for reporting how the campaign delivered once it is running.

AdCP's own documentation says payments, settlement, disputes and makegoods remain account or platform integrations unless a specific AdCP contract covers them. The DealSheet is Alkimi's own deal record, not something AdCP or AAMP defines. Implementation is the responsibility of the platforms that adopt these standards.

What Alkimi Is

Alkimi is a neutral agentic marketplace. It provides a venue where buyer and seller agents built to open standards can negotiate at scale, between buyers and publishers who may not have pre-existing technical integrations. Alkimi is part of IAB Tech Lab's AAMP work and builds to the AAMP framework, and its agent is listed in the IAB Tech Lab Agent Registry.

Identity verification infrastructure. When a buy-side agent connects to Alkimi to begin a negotiation, Alkimi verifies that the agent is authorised by the buying organisation it represents. When a sell-side agent connects, Alkimi verifies it represents the publisher it claims to represent. This verification happens at entry, before any negotiation begins.

Deal record storage. When two agents reach agreement, Alkimi writes the agreed terms to a DealSheet and holds that record in shared state. Both parties can retrieve it independently. Alkimi provides the storage infrastructure that the DealSheet format requires.

Neutral hosting. A buy-side agent and a sell-side agent that have never interacted before can negotiate through Alkimi because Alkimi is a neutral party that both sides trust. The marketplace does not represent either buyer or publisher. It provides the venue where buyer and seller agents can meet and transact.

Why They Are Not in Competition

AdCP and Alkimi are not in competition because they operate at different layers. Open standards such as IAB Tech Lab's AAMP and AdCP define how agents communicate. Alkimi provides a neutral marketplace, working within IAB Tech Lab's AAMP framework. A buy-side agent built to an open agentic standard can work with sell-side agents built to the same standard without a bespoke integration. To do that negotiation with a publisher they have not worked with before, they need a marketplace that both parties trust.

The parallel in conventional programmatic is OpenRTB and an SSP. OpenRTB defines the bid request format. An SSP provides the infrastructure where OpenRTB-compliant DSPs can access publisher inventory. A DSP being OpenRTB-compliant does not mean it can access a publisher's inventory without the SSP. The compliance is the prerequisite; the platform is the infrastructure.

For agentic advertising, the equivalent is an agent built to an open standard such as IAB Tech Lab's AAMP or AdCP. The marketplace is the infrastructure.

What a Buyer Needs to Get Started

A buyer who wants to use agent-to-agent deal negotiation needs two things.

First: a buy-side agent built to an open agentic standard, such as IAB Tech Lab's AAMP or AdCP. This means the agent can exchange structured proposals and responses with sell-side agents built to the same standard, rather than relying on a bespoke integration for each publisher. Without that, every new sell-side relationship needs its own integration work, regardless of which marketplace the agent connects to.

Second: access to a neutral marketplace that provides identity verification, deal record storage, and neutral hosting for agent-to-agent negotiations. Alkimi provides all three, working within IAB Tech Lab's AAMP framework. Without the marketplace infrastructure, the agent has nowhere to conduct negotiations with publishers it has not already integrated with directly.

What Building to an Open Standard Signals

A buy-side agent built to an open agentic standard, such as IAB Tech Lab's AAMP or AdCP, is designed to work with sell-side agents and marketplaces built to the same standard. This is the same portability that OpenRTB created for auction-based programmatic: a DSP that is OpenRTB-compliant can access any OpenRTB-compliant SSP without bespoke integration.

Building to an open standard means buyers are not locked to a single sell-side agent or a single marketplace. If a publisher moves to a different marketplace, or builds their own sell-side agent to the same standard, the buyer's agent can still negotiate with them. The standard creates interoperability. The marketplace provides a starting point for buyers and publishers who want a neutral, governed venue for those negotiations.