Glossary/Adtech & Programmatic/Insertion Order (IO)
Adtech & Programmatic
Insertion Order (IO)
A signed contract between advertiser and publisher or vendor specifying the media to run, dates, quantities, pricing, and terms.
By Brandon Mina·CEO, BrandPilot AI·Updated November 2026
Appears in Lesson 5 of Programmatic 101
Short answer
An insertion order (IO) is a signed contract between an advertiser or agency and a publisher or vendor that specifies the media to run, flight dates, quantities, pricing, and terms. It formalizes direct ad buys and serves as the basis for billing. Programmatic deals often replace manual IOs with automated agreements.