OpenDirect spent most of its life as the standard ad tech discussed but rarely implemented. As of October 2026, that has flipped. Version 2.1 is the quiet plumbing behind AI media agents, and the difference between a custom deals integration that takes up to 350 days of engineering and one that takes roughly 50.
What OpenDirect actually does
OpenDirect is a RESTful API specification maintained by IAB Tech Lab. It lets a buyer search a publisher’s catalogue of advertising products, check price and availability, place an order, attach creative and book guaranteed inventory through software, instead of email, spreadsheets and phone calls.
The flow has four steps:
- Relationship: obtain an organization ID and formal advertiser consent before trading.
- Discovery: search products and check availability and pricing.
- Order: create an Order with currency, budget and dates, then add Lines per product.
- Creative and booking: upload creative, attach it via an Assignment, then call reserve or book.
It replaces the request for proposal, the insertion order and manual trafficking. It carries no bids and sits before delivery.
From a 2013 working group to 2.1
AOL, Yahoo, Microsoft and Yieldex started the working group in June 2013. IAB released OpenDirect 1.0 for public comment in November 2014 and finalised it in January 2015. Version 1.5 added multi-currency support, and 2.0 adopted the AdCOM vocabulary and buyer-seller messaging. Out-of-home then forced the latest rewrite: OAAA released an adaptation in May 2021, and version 2.1 generalised it with ProductTargeting for frames, locations and time.
Adoption remains the big caveat. The 2.1 text itself concedes only a handful of companies have started adopting the API, and IAB Tech Lab publishes no implementation count. Early critics flagged trust, credential management and fear of commoditisation, and the document still names companies that have left the market.
Why AI agents changed the math
In January 2026, IAB Tech Lab chose to extend OpenDirect rather than write new agentic standards. Its reference seller agent is built on OpenDirect 2.1, and Kochava’s AAMP workspace has been in open beta since March 2026, turning campaign briefs into OpenDirect bookings.
The business case is sharp. Adform’s chief technology officer estimated that a custom deals integration with one supply-side platform takes 250 to 350 days of work, against roughly 50 on a shared standard. A buyer agent needs exactly what OpenDirect describes: a catalogue, an availability call and a booking endpoint.
Know the boundaries
OpenDirect is not the same as programmatic guaranteed, which is the transaction type; most programmatic guaranteed volume runs through deal IDs in OpenRTB, without OpenDirect. It is also distinct from the Deals API and from OpenProposal, which handle deal metadata and agent proposals respectively.
What to watch
AAMP 3.0 and OpenProposal were released on September 22, mapping execution to OpenDirect 2.1. The comment window was extended to November 10. No new OpenDirect version has been announced, but the standard has moved from footnotes to the execution layer of agentic buying.
Source: PPC Land
