Inside the bid request
These are field and object names defined by the OpenRTB specification.
- impression objectOne entry per slot being offered in this auction. More than one entry means slots were bundled into a single request.
- format listThe width and height pairs the publisher will accept for that slot.
- tmaxThe exchange's declared maximum wait for responses, in milliseconds, stated per request.
- supply chain objectThe ordered list of systems that handled this impression, with a flag stating whether the list is complete.
- seat bidA buyer's answer, containing the price and a reference to the creative that would run.
Inside the publisher's declaration file
These are positions in an ads.txt record, served at a fixed path on the publisher's own domain.
- system domainFirst position. The system authorised to sell this publisher's inventory.
- account identifierSecond position. The publisher's account inside that system.
- DIRECTThird position, one of two values. The publisher controls the account named in position two.
- RESELLERThird position, the other value. Another party is authorised to sell on the publisher's behalf.
Inside the exchange's seller file
These belong to sellers.json, published by the system rather than by the publisher.
- seller recordOne entry per account the system transacts with.
- seller typeStates whether the account is a publisher of its own inventory or an intermediary passing on someone else's.
- confidential flagMarks a record whose identifying details are withheld while the account itself is still disclosed.
Inside the measurement layer
These come from viewability measurement guidance rather than from any transaction file.
- viewable impressionAn impression meeting both the pixel-share and the continuous-duration requirement for its format.
- measured rateThe share of delivered impressions for which a viewability observation was possible at all — distinct from the share that were viewable.
- invalid trafficEvents excluded from a total by a system's filtering, applied at a stage that varies between systems.
Where these definitions come from
- IAB Tech Lab — OpenRTB specification. Source for every term in the first group.
- IAB Tech Lab — ads.txt and sellers.json specifications. Source for the second and third groups.
- Media Rating Council and IAB — viewable impression measurement guidelines. Source for the fourth group.