PubMatic supports real-time bidding via IAB OpenRTB API 2.5 specification.
OpenRTB enables programmatic bidding on individual ad impressions in real-time auctions. Buyers programmatically purchase inventory on an open exchange that lets many buyers bid in auctions on inventory from multiple publishers. OpenRTB is a highly effective way to reach large audiences through open exchange programmatic buys.
For buyer documentation, see OpenRTB for DSPs/buyers.