An SSP (supply-side platform) is the technology layer on the publisher side of programmatic advertising — it is the seller equivalent of a DSP. An SSP aggregates a publisher's ad inventory, packages it for programmatic sale, manages connections to multiple DSPs and ad exchanges, runs the auction logic, and returns the winning bid to the publisher's ad server for delivery. The SSP enforces floor prices (minimum acceptable CPMs), manages deal IDs for PMP transactions, and provides yield reporting to the publisher. Leading SSPs used in India CTV: Magnite (the largest independent SSP globally, used by major OTT platforms), PubMatic, Google Ad Manager (as both an ad server and SSP), and SpringServe (video-specialist SSP, now part of Magnite).
For India CTV publishers, the SSP relationship determines which buyers can reach your inventory and at what price. A publisher integrated with Magnite and PubMatic simultaneously can accept bids from any DSP that connects to either SSP — broadening their demand pool. SSP fees are typically 15-20% of the winning bid, taken from the gross CPM before the publisher receives payment. This is why net publisher revenue is always less than the gross CPM paid by the advertiser — the SSP and other supply chain participants take margin. Publishers should audit their supply chain regularly: too many SSP integrations creates bid duplication and can confuse buyers, while too few limits demand access. Two to four well-chosen SSP integrations is a reasonable setup for mid-tier India CTV publishers.
Full guide
For a complete explanation, read: SSPs and ad servers for CTV publishers: how the sell-side stack works