PAAPI module

This module allows Prebid.js to support PAAPI, formerly known as FLEDGE.

This document covers the steps necessary for publishers to enable PAAPI on their inventory. It also describes the changes Bid Adapters need to implement in order to support PAAPI.

A related module, fledgeForGpt, adds support specifically for GPT’s component auctions.

Publisher Integration

To use PAAPI, publishers must:

• include this module in their Prebid.js bundle

   gulp build --modules=paapi,...
  

• enable PAAPI, globally or by ad unit, through configuration
• manage the PAAPI auctions. This can be delegated to GPT with the fledgeForGpt module; homegrown solutions are possible with getPAAPIConfig, but out of scope for this document.

Module Configuration

This module exposes the following settings:

As noted above, PAAPI support is disabled by default. To enable it, set the enabled value to true for this module and configure defaultForSlots to be 1 (meaning Client-side auction). using the setConfig method of Prebid.js:

pbjs.que.push(function() {
  pbjs.setConfig({
    paapi: {
      enabled: true,
      defaultForSlots: 1
    }
  });
});

Optionally, PAAPI support can be limited to specific bidders:

pbjs.que.push(function() {
  pbjs.setConfig({
    paapi: {
      enabled: true,
      defaultForSlots: 1,
      bidders: ['bidderA', 'bidderB']
    }
  });
});

Bidder Configuration

This module adds the following setting for bidders:

In addition to enabling PAAPI at the module level, individual bidders can also be enabled. This allows publishers to selectively test with one or more bidders as they desire. To enable one or more bidders, use the setBidderConfig method of Prebid.js:

pbjs.setBidderConfig({
    bidders: ["bidderA"],
    config: {
        fledgeEnabled: true,
        defaultForSlots: 1
    }
});

AdUnit Configuration

All adunits can be opted-in to PAAPI in the global config via the defaultForSlots parameter. If needed, adunits can be configured individually by setting an attribute of the ortb2Imp object for that adunit. This attribute will take precedence over defaultForSlots setting.

The ae field stands for Auction Environment and was chosen to be consistent with the field that GAM passes to bidders in their Open Bidding and Exchange Bidding APIs. More details on that can be found here In practice, this looks as follows:

pbjs.addAdUnits({
    code: "my-adunit-div",
    // other config here
    ortb2Imp: {
        ext: {
            ae: 1
        }
    }
});

Bid Adapter Integration

Chrome has enabled a two-tier auction in PAAPI. This allows multiple sellers (frequently SSPs) to act on behalf of the publisher with a single entity serving as the final decision maker. In their current approach, GPT has opted to run the final auction layer while allowing other SSPs/sellers to participate as Component Auctions which feed their bids to the final layer. To learn more about Component Auctions, go here.

The PAAPI auction, including Component Auctions, are configured via an AuctionConfig object that defines the parameters of the auction for a given seller. This module enables PAAPI support by allowing bid adaptors to return AuctionConfig objects in addition to bids. If a bid adaptor returns an AuctionConfig object, Prebid.js will make it available through getPAAPIConfig, as well as other PAAPI modules such as fledgeForGpt.

Modifying a bid adapter to support PAAPI is a straightforward process and consists of the following steps:

1. Detecting when a bid request is PAAPI eligible
2. Responding with AuctionConfig

PAAPI eligibility is made available to bid adapters’ buildRequests method through the ortb2Imp.ext.ae property of bid requests; it is set to 1 when the browser supports PAAPI and publisher configuration has enabled it as described above. Bid adapters who wish to participate should read this flag and pass it to their server.

When a bid request is PAAPI enabled, a bid adapter can return a tuple consisting of bids and AuctionConfig objects rather than just a list of bids:

function interpretResponse(resp, req) {
    // Load the bids from the response - this is adapter specific
    const bids = parseBids(resp);

    // Load the auctionConfigs from the response - also adapter specific
    const fledgeAuctionConfigs = parseAuctionConfigs(resp);

    if (fledgeAuctionConfigs) {
        // Return a tuple of bids and auctionConfigs. It is possible that bids could be null.
        return {bids, fledgeAuctionConfigs};
    } else {
        return bids;
    }
}

An AuctionConfig must be associated with an adunit and auction, and this is accomplished using the value in the bidId field from the objects in the validBidRequests array passed to the buildRequests function - see here for more details. This means that the AuctionConfig objects returned from interpretResponse must contain a bidId field whose value corresponds to the request it should be associated with. This may raise the question: why isn’t the AuctionConfig object returned as part of the bid? The answer is that it’s possible to participate in the PAAPI auction without returning a contextual bid.

An example of this can be seen in the OpenX bid adapter here or RTB House bid adapter here.

Other than the addition of the bidId field, the AuctionConfig object should adhere to the requirements set forth in PAAPI. The details of creating an AuctionConfig object are beyond the scope of this document.

Related Reading

• fledgeForGpt module
• Protected Audience API (PAAPI), formerly FLEDGE
• Component Auctions
• getPAAPIConfig