Compare two OpenRTB versions field by field

Choose a starting version and a target. The list updates in the browser and links every field to its reference page, so you can plan a migration or check what a partner on an older snapshot will not understand.

From version

To version

144 field changes from OpenRTB 2.5 to 2.6-202606.

Added (125)

Removed (6)

Deprecated (12)

Type changed (1)

Bid.adomain (AnyArray to StringArray)

OpenRTB 2.5 to 2.6-202606 at a glance

The most common migration adds 125 fields, deprecates 12, and removes 6. The removals are the ones that break: fields such as Banner.hmax, Banner.hmin, Banner.wmax, Banner.wmin no longer exist, and a 2.6 validator reports them. The 2.5 versus 2.6 guide walks through the migration.

Where the data comes from

Each version's fields come from the object catalog extracted from that release's specification text, the same catalogs the RTBlint validator uses. Three IAB release tags (2.6-202303, 2.6-202409, and 2.6-202501) shipped a spec file that lagged the release notes, so for those releases the dates follow the notes. The specification versions page links every release's official text.