OpenBid Ledger Specification

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OpenBid Ledger

Infrastructure for Transparent, Auditable Advertising.

OpenBid Ledger is an open source specification for transparent, auditable digital advertising auctions. It defines a modular system in which business bidding is visible within the applicable auction environment and auction activity is recorded in an immutable, verifiable ledger.

The specification is designed to eliminate hidden bidding, undisclosed host intervention, bid manipulation, selective bid suppression, and alteration of historical auction records. Every applicable bid, auction event, administrative action, pricing calculation, advertising delivery event, and settlement event must be recorded according to the specification’s immutable logging requirements.

OpenBid Ledger supports separate Cost Per Click (CPC) and Cost Per Impression Unit (CPIU) advertising models. CPC functionality manages auctions and billing based on validated clicks. CPIU functionality manages auctions and billing based on validated impressions using an Impression Unit defined by the hosting service. The hosting service must disclose the applicable Impression Unit before bidding begins, and the definition becomes part of the permanent auction record.

Specification Objectives

OpenBid Ledger is designed to provide:

Transparent digital advertising auctions
Visible business bidding
Immutable auction records
Verifiable auction outcomes
Host accountability
Independent auditing
Deterministic auction execution
Published and versioned auction rules
Separate CPC and CPIU functionality
Transparent billing and settlement
Tamper-evident historical records
Modular implementation
Vendor-neutral interoperability
Independent hosting and verification

Core Requirements

Visible Bidding

All qualifying bids must be visible within the applicable auction environment.

The system must not provide hidden bids, private host bids, undisclosed bids, preferential bidding channels, selective bid visibility, or other mechanisms that prevent applicable participants from observing qualifying bids.

Each bid must include sufficient information to establish when the bid was submitted, who submitted it according to the system’s identity requirements, the amount bid, the applicable advertising model, the auction to which it belongs, and its current status.

A bid cannot be silently changed. Any withdrawal, rejection, expiration, correction, or other change in state must be recorded as a new immutable event.

Immutable Auction Records

All auction events must be recorded in an append-only ledger.

Historical records must not be deleted, altered, backdated, reordered, or silently replaced. Corrections must create additional records that preserve the original event and identify the subsequent correction.

The ledger must provide mechanisms for detecting unauthorized modification and independently verifying the sequence and integrity of auction events.

Host Accountability

The hosting service provides the infrastructure for operating auctions but must not have an undisclosed mechanism capable of manipulating the auction or its historical records.

The host must not secretly alter:

Bids
Bid timestamps
Bid rankings
Auction results
Clearing prices
Auction rules
Impression records
Click records
Billing calculations
Settlement records
Historical auction events

Administrative actions capable of affecting an auction must themselves be recorded and auditable.

Published Auction Rules

The rules governing an auction must be available to applicable participants before bidding begins.

The rules must identify the applicable auction model, bid requirements, eligibility requirements, ranking method, winner determination method, pricing method, applicable fees, Impression Unit where applicable, and other material conditions.

An active auction must remain governed by the ruleset associated with that auction. Changes to future auctions must not retroactively modify completed or active auction records.

Core Modules

Auction Core Module

The Auction Core Module manages the lifecycle and execution of advertising auctions.

Features include:

Auction creation
Auction identification
Auction scheduling
Auction start and end events
Bid acceptance
Bid validation
Bid ranking
Winner determination
Clearing-price calculation
Auction status
Auction rules association
Auction result generation
Auction event recording
Deterministic auction execution

Bid Ledger Module

The Bid Ledger Module maintains the immutable record of bidding activity.

Features include:

Unique bid identification
Bid timestamps
Bid sequence numbers
Bid amounts
Bidder identification
Bid status
Bid acceptance records
Bid rejection records
Bid withdrawal records
Bid expiration records
Winning bid records
Losing bid records
Append-only event storage
Cryptographic event linking
Tamper detection
Historical record preservation
Ledger integrity verification

CPC Module

The Cost Per Click Module provides advertising auctions based on validated clicks.

Features include:

CPC bid submission
CPC bid visibility
CPC bid ranking
CPC auction execution
Click registration
Click validation
Click attribution
Invalid-click detection
Duplicate-click detection
CPC clearing-price calculation
CPC billing
CPC settlement
Immutable click records
Immutable CPC billing records
Click dispute records

CPIU Module

The Cost Per Impression Unit Module provides advertising auctions based on validated advertising impressions.

Features include:

CPIU bid submission
CPIU bid visibility
CPIU auction execution
Impression registration
Impression validation
Impression attribution
Duplicate-impression detection
Invalid-impression detection
Impression Unit configuration
CPIU clearing-price calculation
CPIU billing
CPIU settlement
Immutable impression records
Immutable CPIU billing records
Impression dispute records

The hosting service determines the number of impressions represented by an Impression Unit. The applicable quantity must be publicly disclosed before bidding begins and must be permanently associated with the applicable auction. The hosting service must not change the Impression Unit during or after an auction.

Advertising Inventory Module

The Advertising Inventory Module manages advertising placements available for auction.

Features include:

Publisher registration
Inventory registration
Placement identification
Inventory classification
Inventory availability
Placement specifications
Inventory status
Minimum bid configuration
Auction eligibility
Inventory ownership records
Inventory change history

Advertiser Module

The Advertiser Module manages businesses participating in advertising auctions.

Features include:

Advertiser registration
Business identification
Campaign management
Budget management
Bid management
Campaign scheduling
Advertising placement selection
Campaign limits
Bid limits
Campaign status
Advertiser activity records

Publisher Module

The Publisher Module manages organizations providing advertising inventory.

Features include:

Publisher registration
Publisher identification
Inventory management
Placement management
Auction configuration
Impression Unit configuration
Floor-price configuration
Publisher settlement records
Publisher audit access
Publisher activity records

Verification Module

The Verification Module allows participants and independent parties to verify auction integrity.

Features include:

Auction verification
Bid verification
Event verification
Ledger verification
Timestamp verification
Cryptographic record verification
Auction result verification
Pricing verification
Settlement verification
Verification certificates
Independent verification
Historical reconstruction

Audit Module

The Audit Module provides access to the records necessary to independently examine auction activity.

Features include:

Auction-level auditing
Bid-level auditing
Advertiser auditing
Publisher auditing
Billing auditing
Settlement auditing
Administrative auditing
Configuration auditing
Ruleset auditing
Fraud-event auditing
Dispute auditing
Audit-log export
Machine-readable records
Human-readable audit reports

Billing Module

The Billing Module records and calculates charges resulting from advertising delivery.

Features include:

CPC billing
CPIU billing
Clearing-price records
Click-based billing
Impression-based billing
Host fee records
Transaction fee records
Refund records
Adjustment records
Billing reconciliation
Billing verification
Immutable billing events

Settlement Module

The Settlement Module manages financial settlement between applicable parties.

Features include:

Advertiser settlement records
Publisher settlement records
Host fee records
Settlement calculations
Settlement reconciliation
Refunds
Adjustments
Settlement disputes
Immutable settlement events
Independent settlement verification

Fraud Detection Module

The Fraud Detection Module identifies suspicious advertising activity without modifying historical records.

Features include:

Invalid-click detection
Automated-click detection
Duplicate-click detection
Impression fraud detection
Duplicate-impression detection
Bot activity detection
Bid manipulation detection
Bid flooding detection
Coordinated bidding detection
Auction interference detection
Suspicious activity records
Fraud findings
Immutable fraud events

Fraud detection must not be used as a mechanism for silently deleting or altering historical auction events. Any determination affecting an existing record must be recorded as a subsequent event.

Dispute Module

The Dispute Module manages disputes involving auctions, bids, advertising delivery, billing, and settlement.

Features include:

Bid disputes
Auction disputes
Click disputes
Impression disputes
Billing disputes
Settlement disputes
Evidence records
Evidence timestamps
Dispute status
Resolution records
Immutable dispute history
Administrative decision records

Governance Module

The Governance Module manages changes to the specification, auction rules, configuration, and system policies.

Features include:

Published governance rules
Ruleset versioning
Configuration versioning
Change proposals
Change records
Approval records
Activation dates
Immutable governance history
Historical rules preservation
Non-retroactive rule changes

Administration Module

The Administration Module provides operational controls while restricting administrative authority over immutable auction records.

Features include:

Role-based administration
Permission management
Administrative identity
Privileged-action logging
Configuration management
System maintenance records
Permission-change records
Administrative audit trails
Immutable administrative events
Separation of administrative duties

No administrative function may provide an undisclosed mechanism for rewriting historical auction records.

Optional Plugin Modules

OpenBid Ledger supports optional plugin modules that extend functionality without changing the requirements of the Core Modules.

Identity Plugin

Provides optional identity verification, business verification, organizational credentials, and participant authentication.

Targeting Plugin

Provides optional advertising targeting functionality, including geographic, contextual, placement, scheduling, and audience targeting.

Analytics Plugin

Provides optional reporting, performance analysis, campaign analytics, auction analytics, and historical trend analysis.

Fraud Intelligence Plugin

Provides advanced fraud analysis, behavioral analysis, anomaly detection, and external fraud intelligence while preserving immutable historical records.

Payment Plugin

Provides integration with external payment and financial settlement systems.

Tax Plugin

Provides configurable tax calculation and tax reporting functionality where required.

Notification Plugin

Provides auction, campaign, billing, settlement, dispute, and administrative notifications.

Reporting Plugin

Provides customizable advertiser, publisher, host, auditor, and public transparency reports.

Federation Plugin

Allows compatible independent OpenBid Ledger hosts to exchange advertising inventory, auction participation, verification information, and other permitted records.

Public Transparency Plugin

Provides public-facing auction information, transparency dashboards, historical auction records, published rules, verification information, and other records designated for public access.

External Audit Plugin

Provides controlled access for independent auditors and verification organizations without granting authority to modify the underlying ledger.

Optional Auction Plugin Modules

OpenBid Ledger supports optional auction plugins that adapt the core auction, bid ledger, verification, audit, billing, settlement, and governance capabilities to additional auction markets.

Each plugin must operate within the core transparency, immutability, auditability, and host-accountability requirements of OpenBid Ledger. Plugins may introduce market-specific rules and data fields but must not weaken or bypass immutable auction records or create undisclosed host control over auction outcomes.

Art Auction Plugin

Supports auctions for paintings, sculptures, photography, digital art, collectibles, and other artistic works.

Features include:

Artwork registration
Artist identification
Ownership records
Provenance records
Artwork descriptions
Condition records
Authentication records
Reserve prices
Bid management
Auction catalogs
Winning bid records
Buyer records
Seller records
Commission calculations
Settlement records
Provenance history
Immutable auction records

Collectibles Auction Plugin

Supports auctions for collectible physical and digital items.

Features include:

Item registration
Category classification
Item condition
Authentication
Ownership history
Rarity information
Reserve prices
Bid management
Auction results
Buyer and seller records
Fees
Settlement
Provenance tracking

Real Estate Auction Plugin

Supports auctions for real property and related property interests.

Features include:

Property registration
Property identification
Seller identification
Property documentation
Auction terms
Bid registration
Deposit requirements
Reserve prices
Bid eligibility
Winning bid records
Buyer records
Seller records
Closing conditions
Settlement records
Transaction history
Immutable auction records

Vehicle Auction Plugin

Supports auctions for automobiles, trucks, motorcycles, recreational vehicles, boats, and other vehicles.

Features include:

Vehicle identification
Vehicle history
Ownership records
Condition reports
Inspection records
Mileage records
Authentication
Reserve prices
Bid management
Auction results
Buyer records
Seller records
Fees
Settlement records

Equipment Auction Plugin

Supports auctions for industrial, agricultural, construction, commercial, and specialized equipment.

Features include:

Equipment registration
Manufacturer information
Model information
Serial number records
Condition reports
Inspection records
Maintenance history
Ownership records
Reserve prices
Bid management
Auction results
Buyer and seller records
Settlement records

Domain Name Auction Plugin

Supports auctions for internet domain names and other transferable digital naming assets.

Features include:

Domain registration
Ownership verification
Domain history
Expiration information
Transfer eligibility
Reserve prices
Bid management
Auction results
Transfer records
Buyer and seller records
Settlement records
Immutable ownership events

Intellectual Property Auction Plugin

Supports auctions involving transferable intellectual property rights where legally permissible.

Features include:

Asset registration
Rights identification
Ownership records
Licensing status
Geographic scope
Duration
Restrictions
Encumbrances
Bid management
Reserve prices
Auction results
Transfer records
Settlement records
Immutable rights history

Ticket Auction Plugin

Supports auctions for tickets, admissions, reservations, and transferable access rights.

Features include:

Event identification
Ticket identification
Seat or access information
Original issuer
Transfer restrictions
Bid management
Auction rules
Winning bid
Transfer records
Fees
Settlement records
Transfer history

Memorabilia Auction Plugin

Supports auctions for historical, cultural, entertainment, and sports memorabilia.

Features include:

Item registration
Provenance
Authentication
Condition records
Ownership history
Documentation
Reserve prices
Bid management
Auction results
Buyer and seller records
Settlement records

Agricultural Auction Plugin

Supports auctions for livestock, crops, agricultural equipment, land-use assets, and other agricultural commodities where applicable.

Features include:

Asset registration
Producer identification
Quantity records
Quality records
Inspection records
Location records
Auction terms
Bid management
Reserve prices
Winning bid records
Buyer and seller records
Settlement records

Commodity Auction Plugin

Supports auctions for physical commodities and standardized commodity lots.

Features include:

Commodity identification
Lot registration
Quantity
Grade
Quality
Inspection
Delivery terms
Bid management
Reserve prices
Auction results
Buyer and seller records
Fees
Settlement
Delivery records

Service Auction Plugin

Supports auctions in which businesses or individuals bid to provide services.

Features include:

Service registration
Provider identification
Service specifications
Qualification requirements
Delivery requirements
Bid submission
Bid comparison
Selection rules
Contract terms
Winning provider records
Settlement records
Performance records
Dispute records

Procurement Auction Plugin

Supports competitive purchasing auctions in which suppliers submit bids to fulfill a defined procurement requirement.

Features include:

Procurement request registration
Buyer identification
Product or service requirements
Supplier registration
Qualification requirements
Bid submission
Bid comparison
Award determination
Contract records
Supplier records
Purchase terms
Settlement records
Audit records

Freelance and Contract Auction Plugin

Supports competitive auctions for freelance work, contracts, projects, and professional services.

Features include:

Project registration
Scope definition
Requirements
Provider qualifications
Bid submission
Proposal records
Selection rules
Award records
Contract records
Milestone records
Payment records
Dispute records
Immutable project history

Energy Auction Plugin

Supports auctions for electricity, renewable energy, capacity, energy credits, and other applicable energy products.

Features include:

Energy product registration
Quantity
Delivery period
Delivery location
Generation source
Bid management
Reserve prices
Auction rules
Winning bid records
Delivery records
Settlement
Verification
Immutable transaction history

Carbon and Environmental Asset Auction Plugin

Supports auctions involving environmental credits, certificates, offsets, and other transferable environmental assets where applicable.

Features include:

Asset registration
Issuer identification
Quantity
Certification
Verification
Vintage information
Geographic information
Ownership history
Bid management
Auction results
Retirement records
Transfer records
Settlement
Immutable asset history

Financial Asset Auction Plugin

Supports auction mechanisms for financial instruments and other regulated assets where legally permissible.

Features include:

Asset identification
Eligibility requirements
Participant verification
Bid management
Auction rules
Pricing rules
Winning bid determination
Transaction records
Settlement records
Regulatory records
Immutable transaction history

Digital Asset Auction Plugin

Supports auctions for transferable digital assets.

Features include:

Asset registration
Asset identification
Ownership verification
Transfer rules
Bid management
Auction execution
Winning bid records
Transfer records
Settlement records
Provenance
Immutable ownership history

Custom Auction Plugin

Provides a standardized framework for creating additional auction types not covered by the predefined plugins.

A Custom Auction Plugin must define:

Auction asset
Participant types
Eligibility requirements
Bid format
Bid visibility requirements
Auction duration
Ranking method
Winner determination
Pricing method
Reserve-price rules
Fees
Settlement rules
Verification requirements
Audit requirements
Dispute procedures
Required immutable records

Custom plugins must inherit the core OpenBid Ledger requirements and may not disable immutable logging, auditability, bid transparency, or host accountability.

Security and Integrity Requirements

OpenBid Ledger implementations must protect the integrity of auction records and prevent unauthorized modification.

The specification requires:

Secure authentication
Access controls
Least-privilege administration
Bid integrity protection
Ledger integrity protection
Tamper detection
Immutable event recording
Privileged-action logging
Security-event logging
Record verification
Independent audit capability

Security mechanisms must not create undisclosed administrative capabilities that undermine the transparency and immutability requirements of the specification.

Transparency Requirements

An implementation must provide sufficient information for applicable participants to understand and verify an auction.

Depending on the applicable access level, this may include:

Auction identity
Advertising inventory
Auction rules
Ruleset version
Bid history
Bid timestamps
Bid status
Winning bid
Clearing price
Impression Unit
Click records
Impression records
Fees
Billing calculations
Settlement calculations
Administrative events
Verification information

The implementation must not selectively expose or conceal auction information for the purpose of manipulating auction participation or outcomes.

Auction Certificate

Each completed auction should produce a verifiable Auction Certificate containing the information necessary to establish the identity, rules, activity, result, and integrity of the auction.

The certificate may include:

Auction identifier
Auction type
Inventory identifier
Ruleset identifier
Ruleset version
Auction start time
Auction end time
Participating bids
Bid sequence
Winning bid
Clearing price
Applicable fees
Impression Unit where applicable
Validated clicks where applicable
Validated impressions where applicable
Settlement information
Ledger verification information
Cryptographic verification data

Non-Retroactive Operation

OpenBid Ledger must preserve the historical state of completed auctions.

New rules, configurations, fees, Impression Unit definitions, algorithms, or policies must apply according to their declared activation conditions and must not silently modify historical auctions.

Historical records must remain associated with the rules and configuration under which the applicable auction occurred.

Specification Branding License (SBL)

Standard

Fully AGPL-3.0+ compliant system
Copyleft enforced for network deployments
Required attribution:
- Roxanne Ardary
- https://www.roxanneardary.com/

Optional

Specification Branding License (SBL)
- Attribution-free commercial deployment
- Pricing based on scale, usage, and deployment scope
- https://roxanneardary.com/openbid-ledger/

License & Notice Requirements

OpenBid Ledger is released under the GNU Affero General Public License v3.0 or later (AGPL-3.0+).

By contributing to any Open Arsenal project, you agree that your contributions will also be released under this license.

Please note the following:

All contributions must comply with the AGPL-3.0+ terms.
Under Section 7 of the license, all redistributions, forks, and derivative works must preserve attribution to: Roxanne Ardary and roxanneardary.com.
OpenBid Ledger specifications are free to use with attribution. A Specification Branding License can be negotiated upon request.
The project’s notice.md file tracks attribution requirements and contributor acknowledgments. Any update that adds new contributors or modifies attribution should also update notice.md.
When submitting a pull request, ensure that any new files maintain the attribution headers where applicable.
Network-deployed versions of this software must also remain fully AGPL-3.0+ compliant, including exposure of source code modifications when applicable under the license.

For full legal details, please refer to the AGPL-3.0+ license and the project’s notice.md file.

Notice – OpenBid Ledger

Attribution Requirement: Under Section 7 of the AGPL 3.0+ license, all redistributions, forks, and derivative works, including network-deployed versions of this project, must provide attribution to Roxanne Ardary and roxanneardary.com.

Contributors

This file tracks contributors and their specific contributions to the project.

Roxanne Ardary, roxanneardary.com – September 1, 2026
Created the repository for OpenBid Ledger. Created the specification for transparent, auditable digital advertising auctions with visible bidding, immutable auction records, and modular Cost Per Click (CPC) and Cost Per Impression Unit (CPIU) functionality.
[Add other contributors here] – [Date]
[Describe contribution in one sentence]