Apostra

New York, NY, United States · Founded 2022

51-200 employees · $100M+

Sourced & current · updated Sep 26, 2026Website

Agentic advertising company, formerly Scope3. Apostra gives advertisers and their AI agents direct access to media across display, CTV, audio and out-of-home, built on the Ad Context Protocol (AdCP) that Scope3 helped create. It rebranded from Scope3 in September 2026, shifting its focus from sustainability measurement to AI agent-led ad buying.