What is OpenRTB and how does it apply to India CTV advertising?

OpenRTB (Open Real-Time Bidding) is the IAB Tech Lab’s protocol that standardises how supply-side platforms (SSPs) send bid requests to demand-side platforms (DSPs) and how DSPs respond with bids. In CTV, the SSP sends an OpenRTB bid request when an ad slot becomes available on a streaming app — within milliseconds, DSPs receive the request, evaluate it against active campaigns, and return a bid (or no-bid). The winning bid’s VAST tag is returned to the app for playback. OpenRTB defines what data the SSP must include about the inventory — device type, app bundle, content category, video parameters — and what format the DSP response must take. Without OpenRTB standardisation, every SSP-DSP integration would require custom engineering.

Key OpenRTB fields for India CTV: device.devicetype = 3 (Connected TV) identifies CTV inventory specifically — buyers should filter on this to exclude mobile. device.ifa carries the device identifier (GAID, TIFA, AFAI) used for frequency capping and audience matching. app.bundle identifies the specific streaming app (e.g., com.jio.hotstar), enabling app-level brand safety exclusions. imp.video contains video parameters: min/max duration, supported VAST versions, skip settings, and playback method. pmp.deals carries deal IDs for PMP transactions. content.cat carries IAB content categories for contextual targeting. Verify that your SSP partner is populating these fields correctly — missing device.devicetype is a common reason CTV inventory is miscategorised as mobile.

SSAI (server-side ad insertion) significantly changes the OpenRTB flow. In standard CSAI, the CTV app makes a live bid request when the ad break starts — DSPs receive real-time signals including the actual device ID, app context, and content metadata. In SSAI, the ad stitching happens on the publisher’s server, which makes the ad request on behalf of the device. The device ID may be passed through (if the publisher supports it) or replaced with a server-level identifier. This means DSPs bidding on SSAI inventory — which includes JioHotstar’s premium supply — may have reduced signal fidelity. Frequency capping based on device ID becomes less reliable, and impression tracking relies on publisher-reported events rather than independent pixel firing.