Prebid Server supports events as described in these GitHub issues:
This endpoint alerts Prebid Server to process the event. Most of the time this just means informing the analytics adapter. But it’s also used in the Programmatic Guaranteed context to affect line item pacing.
| Query Parameter | Required? | Description | 
|---|---|---|
| a | y | Account ID | 
| t | y | Type of the event. Allowed values: winorimp | 
| b | y | Bid ID, expected to be unique so this event can be joined to the auction analytics. | 
| bidder | y | Bidder code | 
| f | n | Format of the PBS response. Values: bis blank, just return HTTP 200 with an empty body.iis image, return HTTP 200 with a blank PNG body | 
| ts | n | Auction timestamp | 
| x | n | Disables or enables analytics. Allowed values: 1to enable analytics or0to disable.1is default. | 
GET https://prebid.site.com/event?t=win&b=1234567890&bidder=rubicon&f=i
POST /vtrackThis endpoint covers there scenario where VAST XML is returned in the response from a client-side adapter. Prebid.js forwards the XML to PBS on a new endpoint that instructs PBS to update the XML and cache it
If the bidder allows PBS to modify their VAST, the server then injects an 
The contents of the 
event:
    url-template: "/event?t=imp&b=%s&f=b&a=%s"
where b=BIDID, a=ACCOUNT
The algorithm for inserting the 
| Query Parameter | Required? | Description | 
|---|---|---|
| a | yes | Account id | 
| Query Parameter | Required? | Description | 
|---|---|---|
| bidid | y | Will enable offline analytics join this impression event to the original auction event | 
| bidder | y | Prebid bidder code | 
| timestamp | n | Auction timestamp as generated by Prebid.js. Useful in offline joins | 
| type | y | Always “xml” | 
| value | y | VAST XML | 
| ttlseconds | n | How long this VAST should be cached | 
POST https://prebid-server.rubiconproject.com/vtrack?a=ACCOUNT
{"puts":[{
    "bidid": "BIDID",
    "bidder": "BIDDER",
    "type":"xml",
    "value":"<VAST.../VAST>",
    "ttlseconds":3600
}]}