Google Authorized Buyers

Google Authorized Buyers is the program through which third-party bidders buy on Google's ad exchange, still widely called AdX. Google publishes an OpenRTB interface for it in JSON and protocol buffers, with Google's own extensions defined in the com.google.doubleclick protocol namespace. The same guide also covers Open Bidding.

Direction and version

Google's exchange sends bid requests to the buyer's bidder endpoint, and the bidder returns an OpenRTB bid response to Google.

OpenRTB 2.6 fields in Google's OpenRTB JSON, which follows its proto2 protocol: flags are 0 or 1 integers, enums are integers, 64-bit integers such as billing IDs are decimal strings, and Native payloads are JSON strings in imp.native.request and bid.adm.

The RTBlint profile google-ab checks requests and responses against the published contract.

Rules beyond the OpenRTB spec

Every impression carries imp.ext.billing_id, the billing IDs a winning bid may be charged to. When an impression offers more than one ID, the bid must pick one of them in bid.ext.billing_id.
Google's protocol adds auction type 3, fixed price, which the specification does not define. On a deal it means the deal floor is the agreed price.
Each bid must declare its landing page through bid.ext.clickurl, an advertiser domain in bid.adomain, or both.
Google does not call nurl or lurl; it supports burl. The ${AUCTION_PRICE} macro expands to an encrypted per-impression price in micros, not a CPM.
A DSA declaration in bid.ext.dsa must include paid, even when payer and advertiser are the same. Values of behalf or paid longer than 100 characters are rejected.
Fields that Google's protobuf defines as a oneof group are mutually exclusive inside one extension.
A bid rendered by a buyer SDK through bid.ext.sdk_rendered_ad must name an SDK listed in app.ext.installed_sdk and supply adomain, a billing ID, crid, w, h, and a declared ad. Google filters a bid that pairs an SDK creative with a separate ordinary or AMP creative.
When the request sets ext.fcap_scope to 1 (none), Google filters bids that carry frequency caps.
Google ignores an event notification token in bid.ext.event_notification_token.payload longer than 128 bytes.
Google sends loss reason 501 for a bid that lost in the mediation waterfall. Creative status codes arrive in ${CREATIVE_STATUS_CODE}, a separate macro from ${AUCTION_LOSS}.

Documented extensions

Path	Meaning
`imp.ext.billing_id`	Billing IDs eligible for the impression, as 64-bit decimal strings.
`bid.ext.billing_id`	The billing ID the bid is attributed to.
`imp.ext.publisher_settings_list_id`	Publisher settings lists that apply to the page.
`imp.ext.allowed_vendor_type`	Creative vendor types the publisher allows.
`imp.ext.dfp_ad_unit_code`	The publisher's Google Ad Manager ad unit code.
`deal.ext.deal_type`	The type of the deal.
`bid.ext.exchange_deal_type`	The deal type the bid is made under.
`bid.ext.impression_tracking_url`	URLs Google calls when the ad renders.
`bid.ext.clickurl`	Landing page URLs of the creative.
`bid.ext.sdk_rendered_ad`	A creative rendered by a buyer SDK installed in the app.
`app.ext.installed_sdk`	Buyer SDKs installed in the app that can render SDK ads.
`ext.fcap_scope`	Which frequency caps the request can honor; 1 means none.
`user.ext.consented_providers_settings`	Ad technology providers the user consented to under Google's Additional Consent.
`regs.ext.dsa`	Digital Services Act requirements for the request.

What the validator checks for this profile

openrtb.profile.google.billing_id_not_offered The selected Google billing ID is not offered by the referenced impression. With a sole ID and no active child seats Google may ignore this field; account configuration is unavailable.
openrtb.profile.google.billing_id_required A Google bid must select ext.billing_id when its impression offers multiple billing IDs.
openrtb.profile.google.collapsible_size_exceeded The expanded Google collapsible-ad the field exceeds the impression's the field.
openrtb.profile.google.deal_billing_id_not_offered The Google deal's non-empty billing_id list does not offer the selected billing ID.
openrtb.profile.google.deal_media_not_offered The bid's mtype is excluded by the Google deal's creative_constraints.mtypes.
openrtb.profile.google.dsa_paid_required Google's DSA declaration requires paid, including when the payer and advertiser are the same.
openrtb.profile.google.event_token_ignored Google ignores event notification token payloads longer than 128 UTF-8 bytes.
openrtb.profile.google.frequency_caps_unsupported Google's request explicitly declares fcap_scope=NONE (1), so frequency-capped bids are filtered.
openrtb.profile.google.landing_page_required Authorized Buyers bids must declare a click URL in ext.clickurl, an advertiser domain in adomain, or both.
openrtb.profile.google.oneof_conflict Google's protobuf oneof permits at most one of these fields.
openrtb.profile.google.sdk_declared_creative_required The SDK declared ad must specify one supported creative content field.
openrtb.profile.google.sdk_field_required Google's selected buyer SDK ad contract requires this bid field, even when the general protocol marks it optional.
openrtb.profile.google.sdk_not_offered Google SDK-rendered ads require an installed_sdk submessage in the corresponding app request.
openrtb.profile.google.sdk_renderer_conflict Google filters bids that select a buyer SDK creative and a separate ordinary or AMP creative.

Loss and status codes

Validate against this contract

Open the tester with the Google Authorized Buyers profile, or run:

rtblint validate --profile google-ab request.json