Published: 17 September 2026

TL;DR: Alkimi is a neutral agentic advertising marketplace where buy-side and sell-side agents negotiate bilateral deals directly, producing a shared DealSheet that both parties hold independently. This piece explains how the connection is made, how proposals are evaluated, and what a completed deal record looks like.

Programmatic advertising has always involved intermediaries: platforms, auction systems, and manual deal-making workflows that sit between buyers and publishers. Alkimi takes a different approach. Rather than running an auction, it provides infrastructure through which buy-side and sell-side agents negotiate directly, producing a bilateral deal record before any impression is served.

This piece explains exactly how that process works, from the first connection to the completed DealSheet.

How Buy-Side Agents Connect to Alkimi

A buy-side agent is an autonomous software agent operating under a human-approved mandate. That mandate defines the parameters within which the agent can act: target audience, CPM ceiling, inventory categories, brand safety requirements, and any other conditions the buyer's team has approved.

When a buy-side agent enters Alkimi, it presents its identity credentials and the parameters it is authorised to negotiate within. Alkimi verifies the agent's identity before any negotiation begins. This identity verification step is a structural requirement. Allowing unverified agents into a marketplace introduces the risk of fraudulent counterparties, so Alkimi checks credentials at the point of entry.

Once verified, the buy-side agent can send deal proposals to sell-side agents representing publisher inventory.

How Sell-Side Agents Evaluate Proposals

A sell-side agent acts on behalf of a publisher. It operates under its own mandate, which defines the parameters within which it can accept or reject incoming proposals. Those parameters typically include CPM floors by inventory category, deal type restrictions, audience data permissions, and buyer category requirements.

When the sell-side agent receives a proposal from a buy-side agent, it evaluates the proposal against its mandate. If the proposed CPM meets the floor, the inventory scope is within scope, and the buyer category is permitted, the sell-side agent can accept the deal autonomously. If any condition falls outside the mandate, the proposal is rejected or escalated to the human publisher for review.

This mandate-based evaluation is what distinguishes an agentic marketplace from a conventional auction. In an auction, the sell-side has no view of buyer intent before the impression fires. In an agentic marketplace, the sell-side agent reads and evaluates the full proposal before agreement.

What the DealSheet Contains

When both agents reach agreement, Alkimi writes a DealSheet: a bilateral deal record that captures the agreed terms at the moment of negotiation. A DealSheet contains the agreed CPM, the inventory scope, the audience conditions, the delivery commitment, and the identities of both agents.

Critically, the DealSheet is held by both parties independently. The buy-side agent receives a copy. The sell-side agent receives a copy. Neither party depends solely on Alkimi's records to verify what was agreed. This independence is what gives the deal record its value. If either party retrieves their copy weeks later and the terms match, the agreement is verified without needing to request records from the marketplace.

The DealSheet is written at the time of negotiation, not reconstructed afterwards. This matters because post-campaign reconstruction relies on platform logs, which are controlled by a single party and can be incomplete. A deal record written at negotiation time, timestamped, and held by both parties is a different category of evidence.

The Role of the Neutral Marketplace

Alkimi's commercial model is independent of deal terms. The marketplace earns its position by providing infrastructure: identity verification, proposal routing, deal record storage, and retrieval access. It has no incentive to alter deal records or favour one side over the other.

This neutrality is a structural property. An exchange that also acts as a principal in deal economics faces a conflict of interest when disputes arise. A neutral marketplace that holds the record but has no stake in its content can provide retrieval access to both parties without that conflict.

How This Differs from a Deal ID

A conventional deal ID is a platform-generated reference that one party uses to access inventory. It is not a shared document. The buyer holds a reference; the publisher holds a different reference. Neither party holds the agreed terms as a single shared record.

A DealSheet is the agreed terms themselves, held by both parties. The distinction becomes significant at reconciliation. With a deal ID, the buyer must request delivery data from the platform. With a DealSheet, the buyer already has the agreed terms and compares them against their own delivery data independently.

Alkimi's approach to agent-to-agent deal negotiation is built around three structural properties: verified agent identity before negotiation, mandate-based evaluation on both sides, and a bilateral deal record written at the moment of agreement. These three properties together make the Alkimi marketplace the operational infrastructure for A2A advertising.