Scope3, the company Brian O'Kelley built to measure the carbon footprint of digital advertising, renamed itself Apostra on September 23, 2026, and now presents its business as a neutral meeting point where software working for brands negotiates with software working for publishers.

In Short

A company that used to help advertisers count the carbon emissions of their online ads has changed its name to Apostra and now makes software that lets AI programs buy and sell advertising on behalf of brands and media owners. It matters because it promises one connection to many kinds of media, from social platforms and podcasts to billboards and radio, without taking a percentage of what advertisers spend. Little has changed for most buyers so far: the disclosed volume is around a million dollars, and the company plans to raise more money before the middle of 2027.

A gateway between two sets of agents

Apostra connects the AI agents working for advertisers with AI agents representing media sellers, so that marketers do not have to build separate integrations with potentially thousands of publishers, platforms and other media providers, according to an interview O'Kelley and his cofounder, Anne Coghlan, gave to Business Insider's CMO Insider.

Advertising, O'Kelley told the publication, has been constrained by fragmented media infrastructure, manual processes and a programmatic market organised around real-time bidding that was never optimised for the most highly valued placements. "You can't buy anything that's not a rectangle with a cookie," O'Kelley said.

The mechanism is different from the auction. No software bids on individual impressions while a page loads. Agents instead automate parts of the slower process of discovering, negotiating, approving and executing media deals, according to Business Insider. The advertiser's agent tells the media owner's agent what the marketer wants to achieve, and the media owner's agent answers with details about its audience and the opportunities it can offer. Online placements, linear television and in-store audio are all in scope, as are creators and so-called clippers, who repost short excerpts of longer videos. Apostra said the approach makes it easier to place ads in "walled garden" social platforms, podcasts and out-of-home advertising, channels that are traditionally harder to reach through programmatic buying.

The company's website pushes the claim further. "For the first time, outdoor and radio sit alongside digital, social and CTV: every kind of advertising, discoverable and buyable in one place, all around the world," it states. Its diagram of a buyer agent runs from applying brand rules and requesting terms through negotiating, booking CTV, out-of-home, social and audio, pacing spend and reporting back, while the seller agent finds opportunities, checks audience fit and scores potential.

For media owners the pitch is a storefront. "Configure an agent through Apostra or bring one you already trust," the site tells sellers. Buyers "can browse or send a brief," while the seller keeps control of price and rules.

Humans stay in the loop

Autonomy is partial by design. Publishers can still require human approval for campaigns, and brands can keep control of the creative and the broader strategy, according to Business Insider. O'Kelley gave the example of a media partner whose AI agent posts proposed ads to a Slack channel so that an employee can review them. The website summarises the split under the heading "Human control, agent scale": people set "the objectives, context and rules," and agents "handle the work required to act on them."

Adapters for the largest platforms

Apostra runs on AdCP, the Ad Context Protocol, which a consortium including Scope3 created last year to give agents a shared language. AdCP arrived on October 15, 2025 with six founding members - Scope3, Yahoo, PubMatic, Swivel, Triton Digital and Optable - and nine core tasks built on Anthropic's Model Context Protocol. Governance sits with the nonprofit AgenticAdvertising.org, and Affinity joined as a founding member in June 2026.

Apostra works with 40 media partners and has built AdCP adapters for major ad platforms, including Google, Meta, Amazon, Reddit and ChatGPT Ads, according to Business Insider. The adapters are Apostra's own work, translating protocol instructions into each platform's existing interfaces. None of the published accounts describe Google, Meta, Amazon, Reddit or OpenAI as partners of Apostra, or as adopters of the protocol.

The large platforms have been opening their own doors to agents instead. Meta opened its ad system to Claude and ChatGPT through AI connectors in April 2026, and Amazon put its Ads MCP Server into open beta earlier that year. Within weeks of AdCP's debut, Google, Amazon and Meta were already building agentic capabilities into their existing systems rather than adopting external protocols. ChatGPT Ads is the youngest destination on the list. OpenAI opened its self-serve Ads Manager to all US businesses on May 5, 2026, and the business passed a $1 billion annualised run rate at the end of August. Every interface change those platforms make lands on adapters maintained by a company of roughly 40 people.

No fee on media, a price on intelligence

The commercial model is the least conventional part of the plan. Apostra does not charge transaction fees or a percentage of media spend, according to Business Insider. It intends to sell add-on intelligence capabilities instead: campaign proposal evaluation, negotiation support, catalogue integration and currency handling. Apostra acknowledged that the model may sound like an ad network but said it functions more like a neutral gateway.

That is a direct challenge to the take rate, the share of spend each intermediary keeps. The Trade Desk chief executive Jeff Green used the company's August 6, 2026 earnings call to criticise competitors wrapping fixed-price and guaranteed products in agentic technology and competing on fee rather than outcome. Those rivals were pricing agentic guaranteed products near 1%, against roughly 20% captured by the incumbent platform. Apostra goes to zero on the media itself.

Fee positioning is familiar ground for O'Kelley. AppNexus, which he co-founded, disclosed in 2017 that it charged sellers 8.5%, part of an effort to position the company as the transparent option in programmatic buying.

A gateway that takes nothing from the media still has to earn something. The Apostra homepage links to a pricing section, yet shows no figures, and neither Business Insider nor AdTechRadar reports what the add-ons will cost. O'Kelley said the company expects to seek additional funding between now and the middle of next year. Scope3 had raised $60 million in total, he said.

How much money has moved

Apostra said it is already running seven-figure campaigns through the system. O'Kelley told Business Insider that an unnamed major brand began with a $1 million US campaign in April, then expanded the experiment into several other markets and channels. Adweek, which also interviewed O'Kelley for the rebrand, put the platform's agentic buys at roughly $1.2 million, according to a post by its reporter Kendra Barnett. O'Kelley also told Adweek he expects agentic revenue to overtake sustainability revenue within a year, according to a summary of that interview published by tipsheet.

Read together, the two accounts suggest that one advertiser supplies most of the disclosed volume. If the platform had handled about $1.2 million and a single brand's US campaign started at $1 million, then the "seven-figure campaigns" Apostra describes rest largely on that April test and its expansion. Neither publication names the brand or breaks the figure down by market or channel. Many early campaigns ran through brands' agencies, which let marketers test agentic buying without rebuilding their internal processes, according to Business Insider.

The industry yardsticks are larger, but not by as much as the enthusiasm around agentic AI might suggest. Magnite chief executive Michael Barrett said in July that the most optimistic forecasts put agentic advertising spend at $600 million to $700 million in 2027. A Prebid webinar in May 2026 described early spend in the low six figures. ChatGPT's ad business was taking in roughly $83 million a month at its run-rate milestone, about 70 times Apostra's disclosed total.

Price evidence remains mixed. DataBeat's June report found conventional programmatic buyers clearing at $6.95 CPM against $6.13 for agentic buyers, with agentic demand entering 86% fewer auctions. Stated demand runs well ahead of spend. AdTechRadar pointed to IAB's 2026 Outlook Study, based on more than 200 US brand and agency buyers, in which two-thirds said they were focused on agentic AI for ad buying and campaign execution, the figure IAB published in January 2026.

Carbon, then quality, then agents

AdTechRadar summarised the route in a September 24 piece headlined "Scope3 Pivots Yet Again." In its telling, a company started to reduce carbon emissions in advertising pivoted to helping companies understand the carbon impact of AI, bought Adloox, moved into media quality, sold Adloox, left media quality and has now become "the company it increasingly seemed to want to be."

The archive bears out the outline. Scope3 was supplying carbon data to Yahoo's SSP for green private marketplaces in January 2023, its model had measured more than 130 billion impressions for TikTok advertisers by mid-2025, and it aligned its emissions methodology with GMSF v1.2 on October 1, 2025. The verification detour opened with the Adloox purchase on November 4, 2024, which led Google to rename Adloox references across Display & Video 360 in July 2025, and closed when Peer39 bought Adloox on June 2, 2026. An agentic thread ran underneath. Scope3 presented its Agentic Media Platform alongside an Amazon DSP integration in March 2025, was the first buyer on Swivel's agent-to-agent transactions in November 2025, and acted as buyer agent in Magnite's first seller agent test in December 2025.

Money, staff and the turning point

The funding traces back to an earlier venture. In 2019 O'Kelley cofounded CMDTY, later renamed Waybridge, which ran a supply-chain platform tracking the movement of raw materials, according to Business Insider. Scope3 began as a side project. Waybridge returned some of its $30 million Series B funding to investors, who reinvested $20 million from a seed round in Scope3.

O'Kelley said he had planned to expand beyond carbon tracking as early as 2022. The turning point came in 2025, when companies began scaling back sustainability programmes; until then, he said, revenue had been "doubling" each year. The company put all of its focus on the Apostra project "when it became clear the sustainability business wasn't going to double," he told Business Insider.

Headcount absorbed the cost. Two rounds of layoffs reduced staff from more than 100 to about 40, according to Business Insider, which placed both rounds in the past year. The dates sit slightly outside that window: commercial team cuts came in August 2025, when Tim Collier became chief commercial officer, and engineering and sales reductions followed in February 2026. O'Kelley called the rebrand the company's "burn the boats" moment. "It's just really hard to make money in programmatic when your future vision is to kill programmatic," he said.

Former staff have been less charitable. AdTechRadar cited Glassdoor reviews from former employees, one of whom wrote that "the environment feels chaotic and unstable." Its editorial verdict was nonetheless measured: this pivot "might actually make the most sense," and Apostra "is a smarter play as a business," with more of an opportunity to secure funding, something Scope3 "seemingly struggled with." The publication added a warning: "if another pivot comes, it will likely be one too many."

Two stories behind one name

Apostra's own explanation was quoted in a post on X by Simon Harris on September 23: "The name Apostra comes from apostrophē, the Greek word for a turning away. For us, it represents a turn away from how advertising has been assembled before..." O'Kelley gave Business Insider a lighter version. "The reason we called this company Apostra is because we were joking about apostrophes, which take out unnecessary letters and words," he said. "You go from 'cannot' to 'can't' and you lose nothing."

The old name survives. Apostra's site sends visitors "Looking for Sustainability" to "Scope3 by Apostra," so the carbon product continues under its former brand. Another name is absent from every account of the rebrand: Interchange, which Scope3 used for its agentic buying platform and through which InMobi opened CTV and mobile in-app supply to buying agents on June 3, 2026. Whether Apostra replaces that product name or sits above it is not stated.

A protocol with a rival

O'Kelley's biography brings credibility and baggage in roughly equal measure. He was credited with helping to invent the ad exchange at Right Media, which sold to Yahoo shortly after he left; he had been fired as chief technology officer after telling the board not to take the deal, according to Business Insider. AppNexus, his next company, sold to AT&T for a reported $1.6 billion in 2018. Joseph Hirsch, chief executive of Swivel, called him the "master of the hard pivot" last year.

The larger dependency is the protocol. Apostra calls itself neutral, yet AdCP has been closely associated with O'Kelley and Scope3 since its debut, and Ari Paparo questioned in November 2025 whether agents could overcome the problems that stalled programmatic direct deals. IAB Tech Lab has built a parallel framework. It named the Agentic Advertising Management Protocols, or AAMP, on February 26, 2026, and its chief operating officer, Shailley Singh, counted 13 functions that AAMP and AdCP share in August. AAMP 3.0 followed on September 22, 2026, the day before the rebrand, according to AdTechRadar's listing of its own coverage.

O'Kelley has argued that the protocol reaches beyond display; in January he wrote that AdCP works for linear TV, CTV, out-of-home and social platforms. The open-source supply side has grown around it, with Prebid.org taking stewardship of an AdCP sales agent on January 29, 2026. Competition for the gateway role is arriving from sellers, though. Magnite, whose first seller agent test used Scope3 as the buyer, added its own buyer agent in April 2026 and opened an Orchestration layer in June to connect buyer agents with sell-side supply. Its first EMEA agentic campaign, with Amnet France, ran through Magnite's own buyer agent.

The carbon question returns

AdTechRadar did not miss the irony. WE7 AI estimates that agentic advertising could produce two to four times more carbon emissions per impression than traditional programmatic, because of the additional AI computing involved, according to AdTechRadar. The publication did not describe WE7 AI's methodology, and the estimate has not been independently verified.

The underlying cost is real enough. Draft Digital collapsed twelve MCP calls into a single buyer agent to contain token consumption, and publishers have not dropped the environmental issue: 40% of UK publisher and platform respondents named monitoring programmatic carbon emissions their most important issue for 2026. The Scope3 carbon product now sits inside a business that, on that estimate, raises emissions per impression.

What remains unproven

Procurement at large brands often lags new trends, and much ad buying still rests on human relationships and dealmaking, which is why events such as the annual US TV upfronts endure, Business Insider noted. Coghlan said adoption will require organisational change at some marketers. Some large companies, she said, are already experimenting with thousands of internal AI agents across departments but have not worked out how to connect them to media buying. "We're not expecting you to throw everything out the window," O'Kelley said, adding that human relationships and craft will always matter in advertising.

What Apostra offers media buyers, for now, is breadth on paper and disclosed volume in the low seven figures. Three questions will decide whether that changes. Will the add-ons earn enough, without a take rate, before the raise planned by mid-2027? Will adapters built by so small a team keep pace with platforms building their own agent interfaces? And will the contest between AdCP and AAMP settle before buyers are asked to pick one? For a company that has changed direction as often as Scope3 did, the next funding round may say more about Apostra than the new name does.

Timeline

Summary

Who: Scope3, now renamed Apostra, led by chief executive Brian O'Kelley and cofounder Anne Coghlan, with about 40 staff after two rounds of layoffs. The company works with 40 media partners and has built AdCP adapters for Google, Meta, Amazon, Reddit and ChatGPT Ads.

What: Scope3 rebranded as Apostra and made agentic media buying its core business, positioning itself as a neutral gateway that connects advertisers' AI agents with sellers' agents through the Ad Context Protocol. It charges no transaction fee or percentage of media spend and plans to sell add-on intelligence capabilities instead. Disclosed volume is in the low seven figures, led by one unnamed brand's $1 million US campaign that began in April 2026.

When: The rebrand became public on September 23, 2026, with AdTechRadar's analysis following on September 24. The company expects to seek additional funding by the middle of 2027.

Where: Apostra targets digital, social, CTV, audio, podcasts, out-of-home and linear TV worldwide; its first large campaign ran in the United States before expanding into other markets. The sustainability product continues as Scope3 by Apostra.

Why: O'Kelley said the sustainability business stopped doubling in 2025 as companies scaled back programmes, and that making money in programmatic is hard when the company's vision is to replace it. Buyers say they are prioritising agentic AI, but measured agentic spend across the industry remains small, and a rival IAB Tech Lab framework overlaps with the protocol Apostra depends on.