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Brief
Scope3 was rebranded to Apostra (Sep 2026)— see Apostra for current status.
Scope3

Scope3

AdTechscope3.com

Scope3 gave advertisers and media buyers a rigorous emissions model to measure and reduce the carbon footprint of programmatic advertising; that capability now continues as Scope3 by Apostra alongside a new focus on AI-agent-led media buying.

Last updated Oct 11, 2026 by the ATDb Editorial Team · Connections updated Oct 12, 2026

In the news
Founded
2022
HQ
New York, NY, United States
Connections
31

AI-drafted from public sources7 sources cited

At a glance

Employees
51-200
Funding
$34M
15integrations1competitors1acquisitions
Marketing Technology

About

Pioneer in programmatic advertising carbon measurement; rebranded as Apostra in 2026 to lead AI agent-driven media buying

Scope3 was an advertising sustainability company co-founded by Brian O'Kelley, the co-founder of AppNexus, and Anne Coghlan. It built an emissions model for programmatic advertising that let advertisers, agencies, DSPs, SSPs and publishers measure and reduce the carbon footprint of their media buying. Its investors included GV and Venrock. In November 2024 Scope3 acquired the ad verification company Adloox, which it sold to Peer39 in June 2026. In October 2025 it was one of the founding members of the Ad Context Protocol (AdCP), an open standard for AI agents that buy and sell advertising, and it moved its business toward agent-led media buying. On September 23, 2026 the company renamed itself Apostra to mark that pivot. Its carbon-measurement product continues under the Scope3 by Apostra brand.

Business model

SaaS

Target market

Enterprise

What they offer

  • Scope3 Emissions Model

    A granular carbon-emissions measurement model for programmatic advertising covering advertisers, agencies, DSPs, SSPs and publishers — now continued as Scope3 by Apostra.

  • Adloox (divested)

    Ad verification platform acquired by Scope3 in November 2024 and subsequently sold to Peer39 in June 2026.

  • Ad Context Protocol (AdCP)

    An open standard for AI agents that buy and sell advertising, co-founded by Scope3 in October 2025 as part of its pivot toward agent-led media buying.

Key features

Granular per-impression carbon emissions measurement for programmatic mediaSupply-path emissions scoring for DSPs and SSPsPublisher-level sustainability reportingFounding participation in the Ad Context Protocol (AdCP) open standardAI agent-led media buying infrastructure (post-pivot, now under Apostra brand)

Use cases

Measuring the carbon footprint of programmatic ad campaignsReducing emissions through greener supply-path optimizationSustainability reporting for advertisers and agenciesAI agent-based media buying and selling (post-pivot)

Customer segments

Advertisers and brandsMedia agenciesDemand-side platforms (DSPs)Supply-side platforms (SSPs)Publishers

Tech & specs

Technology stack

Cloud-based emissions modelingProgrammatic advertising APIsAI / machine learning (agent-led media buying)Open standard protocol (AdCP)

Security & compliance

GDPRCCPA

Deployment

Cloud

API

Yes

Explore further

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