Build and submit an OpenRTB 2.6 bid request as an SSP and validate a bid response

Steps

1. Construct a JSON BidRequest object conforming to the OpenRTB 2.6 specification, populating the id, imp array (with banner or video object), site or app object, device, and user fields
2. Populate the imp[].banner or imp[].video object with supported sizes/protocols, the imp[].bidfloor and imp[].bidfloorcur fields, and the imp[].ext object for exchange-specific extensions
3. Include a SupplyChain (schain) object in the BidRequest.ext.schain field to declare all nodes in the reseller chain per the IAB SupplyChain spec
4. POST the BidRequest via HTTP POST with Content-Type: application/json (or application/x-protobuf for protobuf mode) to each bidder's endpoint, respecting the auction timeout (typically 100-300ms)
5. Parse the BidResponse: check for seatbid arrays, validate that the bid price meets or exceeds the floor, select the winning bid, and return a win notice by calling the nurl (win notice URL) on the winning bid object
6. For CTV/video impressions using dynamic ad pods, populate the imp[].video.podid and podsequence fields introduced in OpenRTB 2.6 to indicate pod position and enforce competitive exclusions