# OpenRTB 2.x Protocol

**Canonical:** https://apis.io/apis/iab-tech-lab/openrtb/  
**Provider:** IAB Tech Lab — https://apis.io/providers/iab-tech-lab/  
**Documentation:** https://iabtechlab.com/standards/openrtb/

OpenRTB 2.x Protocol is one of 9 APIs that [IAB Tech Lab](https://apis.io/providers/iab-tech-lab/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include Real-Time Bidding, Programmatic, and Protocol Buffers. The published artifact set on APIs.io includes API documentation and a changelog.

OpenRTB is the real-time bidding protocol between ad exchanges and bidders. IAB Tech Lab publishes the 2.x specification (current release 2.6-202606) with a Protocol Buffers definition (package com.iabtechlab.openrtb.v2, 69 messages) that is maintained in lockstep with the specification and is the standard binary encoding for OpenRTB.

## Machine-readable artifacts (4)

- **Documentation** — https://github.com/InteractiveAdvertisingBureau/openrtb2.x
- **Protobuf** — https://raw.githubusercontent.com/api-evangelist/iab-tech-lab/refs/heads/main/grpc/iab-tech-lab-openrtb-v2.proto
- **ChangeLog** — https://github.com/InteractiveAdvertisingBureau/openrtb2.x/releases
- **Protobuf** — https://raw.githubusercontent.com/api-evangelist/iab-tech-lab/refs/heads/main/grpc/iab-tech-lab-grpc-index.yml

## Other IAB Tech Lab APIs (8)

- [OpenDirect API](https://apis.io/apis/iab-tech-lab/opendirect-api/)
- [IAB Agentic Advertising API](https://apis.io/apis/iab-tech-lab/agentic-advertising-api/)
- [Seller Agent API](https://apis.io/apis/iab-tech-lab/seller-agent-api/)
- [Buyer Agent API](https://apis.io/apis/iab-tech-lab/buyer-agent-api/)
- [AdCOM Protobuf](https://apis.io/apis/iab-tech-lab/adcom/)
- [Agentic RTB Framework gRPC](https://apis.io/apis/iab-tech-lab/agentic-rtb-framework/)
- [VAST and VMAP Schemas](https://apis.io/apis/iab-tech-lab/vast/)
- [Supply Chain API](https://apis.io/apis/iab-tech-lab/supply-chain-api/)

## Tags

Real-Time Bidding, Programmatic, Protocol Buffers

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/iab-tech-lab/openrtb/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/iab-tech-lab/.