What is OpenRTB?

OpenRTB is an IAB Tech Lab protocol for real-time bidding (RTB). It defines how supply-side platforms send structured bid requests and how demand-side platforms reply with bids, creatives, and metadata. The goal is one shared format so exchanges, DSPs, and SSPs can trade impressions in milliseconds without custom one-off APIs for every pair of systems.

Table of Contents

  1. What happens in an OpenRTB auction?
  2. What sits inside a bid request?
  3. Why OpenRTB matters for fraud and wasted spend

What happens in an OpenRTB auction?

When a user loads a page or app with ad slots, the publisher side packages context into a bid request: site or app identifiers, impression sizes, user/device hints, regulations, and optional extensions (such as supply-chain data). The SSP broadcasts that request to eligible DSPs.

Each DSP evaluates the request against advertiser rules, bids or passes, and returns a bid response with price, creative markup, and tracking. The SSP runs the auction (often second-price), notifies the winner, and returns the ad to the client. The whole round trip typically must finish within a tight timeout.

What sits inside a bid request?

Common objects describe the impression, publisher property, device, geo, and privacy signals. Buyers use those fields for targeting, frequency caps, and brand-safety filters. The exact shape changes by OpenRTB version; mobile, video, native, and CTV placements add their own objects.

OpenRTB is not the only way to buy media (deals, programmatic guaranteed, and walled gardens use other workflows), but it is the main language of the open auction web and in-app RTB.

Why OpenRTB matters for fraud and wasted spend

Standard fields make it easier to apply policy at scale: block bad categories, enforce geography, read supply transparency signals, and route spend toward verified paths. They do not guarantee truth. Fields can be wrong or manipulated, which is why ad fraud and invalid traffic remain separate problems.

Click fraud on search or social is a different stack, but the same discipline applies: treat reported context as hints, then validate outcomes. Teams often pair buy-side hygiene with how fraud is detected in analytics and with click-level tools that flag suspicious clicks. For background on tactics in display and video, see ad fraud techniques and display ad fraud.

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Device and network context (for example OS and environment signals) still matter for separating real users from automation.

Frequently Asked Questions

  • Is OpenRTB the same as programmatic?

    Programmatic is automated ad buying with software and data. OpenRTB is the IAB Tech Lab protocol that standardizes bid requests and responses between SSPs and DSPs in real time. Open web and in-app RTB usually use it; other programmatic paths use different mechanics. Programmatic is the umbrella; OpenRTB is one widely shared standard inside it.

  • Does OpenRTB stop bots?

    No. OpenRTB moves auction data; it does not prove a human saw the ad. Spoofed supply and invalid impressions still need SSP filters, measurement rules, advertiser policies, and dedicated protection. Treat request fields as hints, then validate outcomes on your side. For how automated traffic fits in, read what is a bot and what is ad fraud.

  • Why do OpenRTB integrations still break?

    Partners run different OpenRTB versions, optional extensions, timeouts, and required fields. Creative IDs, consent strings, and ad markup must match each exchange’s rules or bids can fail without a clear error. Plan time for partner-specific testing, log review, and field mapping rather than assuming one generic build works everywhere.

Abisola

Abisola

Meet Abisola! As the content manager at ClickPatrol, she’s the go-to expert on all things fake traffic. From bot clicks to ad fraud, Abisola knows how to spot, stop, and educate others about the sneaky tactics that inflate numbers but don’t bring real results.