how ads get there
Delivery models
Same lifecycle, three different shapes. Which one a publisher runs decides who gets first look and where the latency goes.
Waterfall vs Header Bidding
Waterfall
option aPublisher tries SSPs one at a time. The first that fills above the floor wins.
Pros
- · Simple to reason about
- · Cheap to operate
Trade-offs
- · Sequential calls = latency
- · Hidden price ceiling
- · Top SSP gets first look
Header Bidding
option bAll SSPs are asked in parallel from the page header. Winning bid is passed to the ad server as a competing line item.
Pros
- · All SSPs see all impressions
- · Higher clearing prices
- · Price discovery is real
Trade-offs
- · Client weight (Prebid.js)
- · Timeout management
- · Complex setup
CSAI vs SSAI
CSAI
option aClient-Side Ad Insertion: the player fetches content and ads as separate streams. The classic web pattern.
Pros
- · VPAID & client interactivity
- · Easy to track client-side
- · Standard player SDKs
Trade-offs
- · Visible buffering at break
- · Ad blockers can stop the call
- · Inconsistent on CTV
SSAI
option bServer-Side Ad Insertion: a service stitches ad segments into the HLS/DASH manifest. The player sees one stream.
Pros
- · Seamless playback
- · Bypasses most ad blockers
- · Works on every CTV
Trade-offs
- · No VPAID
- · Tracking through proxy
- · Manifest manipulation cost
Open auction vs PMP vs PG
Open auction
option aAnyone can bid. Lowest floor, highest density. Default for unsold inventory.
Pros
- · Maximum demand
- · Best price discovery
Trade-offs
- · Brand safety risk
- · Lowest priority in ad-server hierarchy
PMP / PG
option bPMP: invite-only auction with a deal ID. PG: fixed price + fixed volume, no auction — closest thing to a direct buy in programmatic.
Pros
- · Curated buyers
- · Fixed price (PG) or floor (PMP)
- · Higher priority than open
Trade-offs
- · Lower fill if buyer pulls back
- · Deal-ID plumbing per partner