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OOHDI is a distributed, open source, globally unique identifier for OOH inventory

Read the spec

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Enter an OOHDI-compatible screen ID to validate it against the specification.

Try org.oohdi.example-media-owner/oohdi/emp-001 as an example valid OOHDI.

OOHDI information graphic

Why OOHDI exists

OOHDI creates an open source, globally unique, decentralized identifier for sellable out-of-home inventory. It helps buyers, sellers, creative teams, and media operators identify the same display consistently across fragmented systems.

Without a common identifier, inventory is hard to discover, verify, validate, and de-duplicate across SSPs, DSPs, CMS platforms, and media owner systems.

Who it is for

  • Media owners
  • SSPs and DSPs
  • Agencies and buyers
  • Creative teams
  • OOH registry and ad-tech providers

Example OOHDI identifiers

OOHDI identifiers follow a reverse-DNS namespace and a canonical inventory path.

  • com.foobaroutdoor/oohdi/ab-1234-c
  • uk.co.barfoodmedia/oohdi/98765

What is a registry?

A registry is the authoritative public service that exposes inventory data for a media owner namespace. It is the source of truth for screen records, metadata, and canonical OOHDI identifiers.

Registry discovery happens through DNS, using an _oohdi.<domain> TXT record that points to the authoritative registry host.

Who owns OOHDI?

OOHDI is decentralized with no owner organization. It operates on principles of DNS and is designed to ensure no single entity controls IDs.

Who should build registries?

The following companies should consider exposing their inventory via an OOHDI compatible registry:

  • Digital Signage CMS systems
  • Digital Signage player systems and CRM systems
  • Static billboard inventory systems
  • Medium to Large OOH companies that maintain their own source of inventory truth

Audience and use cases

Media Owners

Ensure that your displays can be found and verified by any buyer

Agencies and Media Buyers

Verify that the displays that you are buying exist, are active and are in places you want to buy

Creative Teams

Validate that the ad creatives you are building match the size specifications for the displays you are designing for.

Content Management Systems (CMS)

Create a common way to represent, publish and promote display inventory for your users

DSP's

De-duplicate and validate display inventory across all SSP's

SSP's

Verify that ever changing media owner inventory is active, up to date, and accurately described

Ad Tech Providers

Innovate and build tools that interact with display data

Implementation

Media Owners

  1. Request that your CMS vendor or inventory management vendor enable an OOHDI compatible registry for your inventory
  2. Publish the OOHDI DNS record to your nameservers
  3. Your existing IDs become OOHDI compatible IDs automatically

Registry Vendors

  1. Map your existing customer IDs to OOHDI compatible IDs (e.g. "screen-id-1" becomes "com.yourcustomername/oohdi/screen-id-1")
  2. Expose the 2 OOHDI compatible endpoints
  3. Enable OOHDI for your customers and notify them of the correct DNS record to publish

Getting started guides

Overview

For media owners

For registry owners

Request for Comments

This is a DRAFT proposal for public review. Comments should be submitted either as issue comments on the GitHub repository or as pull requests on the GitHub repository.

Open OOHDI GitHub repository

Submit an issue comment | Submit a pull request

More information

The full OOHDI specification, examples, and code are available in the project repository.

Open OOHDI GitHub repository