OpenRTB is the IAB Tech Lab's standard protocol for real-time programmatic ad auctions. It defines the JSON format and field structure for the bid request (sent by an SSP to DSPs) and the bid response (returned by DSPs to the SSP). Every programmatic CTV auction runs over OpenRTB.
The key OpenRTB fields that matter in CTV bid requests:
- imp.video: The video ad unit parameters — allowed durations, skip rules, placement type (in-stream vs out-stream), minimum bitrate. Buyers use these to ensure only compatible creatives bid on each slot.
- app.bundle: The CTV app's store ID (e.g., the Google Play or Apple TV app bundle). This is how DSPs and fraud filters identify which publisher's inventory is in the bid request. Spoofed app.bundle values are the primary vector for CTV ad fraud — buying supposed JioHotstar inventory that is actually a fraudulent app.
- device.ifa: The device's advertising identifier (IDFA on Apple, GAID/AIFA on Android/Fire TV). Used for frequency capping and audience matching across impressions.
- device.ip: Household IP address. Used for household-level attribution and geo targeting.
- content: Content metadata — genre, language, episode details, livestream flag. Used for contextual targeting and content exclusions.
The current standard is OpenRTB 2.6, which added native CTV support including pod bidding fields and improved content object fields. OpenRTB 2.5 is still widely used in India CTV, with 2.6 adoption growing as SSPs upgrade.
Related questions
For the full technical reference, see the OpenRTB for CTV knowledge base article.