Metadata
Metadata provides the semantic context that gives meaning to on-chain registry records. Where the Regen Ledger captures canonical state—credit classes, projects, batches, issuances, transfers, and retirements—metadata describes what those records represent and the relationships between them.
In the Regen Network Ecosystem, metadata acts as the connective tissue between projects, credits, claims, and evidence to facilitate the creation of machine-readable knowledge graphs that support advanced queries, interoperability, and transparency across applications and initiatives.
How Metadata is Used
Metadata plays several essential roles throughout the registry system, describing core entities, connecting ecological claims to evidence, and supporting application features and governance processes.
Credit Classes, Projects, and Credit Batches: Metadata captures and organizes essential information about credit protocols, projects, and credit batches—defining issuance requirements and processes, documenting project characteristics and impacts, and tracking credit batch states through their lifecycle from protocol definition to credit retirement.
Data, Claims, and Evidence: Metadata structures the relationship between ecological claims and their supporting evidence. Metadata constructed in RDF and attached to an anchor event using the regen data module can creates a verifiable chain linking the claim to specific pieces of evidence, verification processes, and outcomes also anchored with RDF metadata sets. This chain remains intact and queryable even when the underlying evidence data is permissioned or private, providing transparency around the verification process while respecting data sovereignty.
Governance Decisions: Metadata captures the governance processes and decisions that affect protocols, projects, and credits. This includes recording proposal submissions, voting outcomes, and parameter changes. The metadata creates an auditable trail of decision-making that helps establish legitimacy and enables stakeholders to understand how and why changes were made.
IRIs, Metadata, & the Ledger
International Resource Identifiers (IRIs)
The Regen Ledger does not store metadata directly. Instead, it stores content-addressed identifiers—Internationalized Resource Identifiers (IRIs)—that point to metadata stored off-chain.
An IRI acts as a cryptographically derived fingerprint of the metadata document it represents. When metadata content changes, a new IRI is generated, creating an immutable reference to the updated content while preserving access to historical versions.
Metadata documents themselves are stored off-chain in locations such as IPFS, Postgres databases, or custom storage solutions. They can be stored in various formats (though JSON-LD is commonly used in the Regen ecosystem) and may include rich structured information such as ecological classifications, SDG mappings, monitoring protocols, stakeholder profiles, and verification details.
This architecture preserves data integrity through cryptographic verification while enabling privacy controls, version history, and distributed contribution—all while keeping the ledger lightweight and verifiable.
How Metadata Is Used in the Ecocredit Module
The ecocredit module includes a metadata field that can store an IRI. These IRIs act as stable pointers linking on-chain entities to their semantic descriptions:
Credit Classes typically use this field to reference metadata describing protocol details, methodology requirements, eligible activities, governance parameters, and credit type definitions.
Projects typically used to reference metadata containing geographic extent, ecosystem characteristics, participant information, management actions, and project-specific context.
Credit Batches typically used to reference verification results, monitoring periods, vintage information, ecological claims, and the specific outcomes that justified issuance.
Beyond the ecocredit module, IRIs appear throughout the registry: governance proposals reference metadata, the data module anchors metadata for datasets and claims, and project updates generate new IRIs that link to previous ones. This creates a cohesive semantic layer across the system.
Resource Description Framework (RDF)
The Resource Description Framework (RDF) provides the foundation for Regen's metadata architecture. RDF is a standard model for representing and describing resources on the web using a simple, graph-based structure that expresses data in triples. Each triple consists of:
Subject: The resource being described (e.g., "Project A", "Evidence B")
Predicate: The property or relationship of the resource (e.g., "has location," "authored by")
Object: The value or target of the relationship (e.g., "Colombia," "Terrasos")
This simple but powerful structure allows complex relationships between different pieces of information to be expressed in a consistent, machine-readable way. Its graph-based model and use of unique identifiers enable rich semantic relationships and scalability, making it ideal for building linked data applications.
Rather than storing isolated attributes, RDF emphasizes how information connects—projects to locations, locations to ecosystems, claims to evidence. The result is a semantic graph that supports sophisticated queries, automated reasoning, and cross-dataset interoperability.
Full details on RDF vocabularies, schemas, data types, and implementation conventions appear in the Data Standards & Framework section.
Metadata Graph API
The Metadata Graph API provides a unified interface for retrieving and generating metadata via IRIs. Applications, indexers, and external tools rely on the API to resolve, traverse, and construct metadata graphs.
Key endpoints:
GET /data/v2/metadata-graph/{iri}
Resolves an IRI and returns the corresponding metadata graph (typically in JSON-LD). The API handles resolver backends such as IPFS and HTTPS, abstracting away storage details.
POST /data/v2/iri-gen
Accepts a metadata document and returns the deterministically generated IRI for that content. Used when creating new projects, credit classes, claims, evidence references, or project updates.
These endpoints allow applications—including the Regen App—to construct, publish, and display linked metadata without managing storage or hashing logic directly.
For full Swagger specifications, see the Metadata Graph API Docs.
Why Metadata is Important
Metadata forms the foundation for trust and transparency in environmental markets by creating verifiable chains of evidence that stakeholders can track and audit. The public nature of metadata, even when underlying data is private, enables verification of claims while respecting data sovereignty and privacy requirements.
Interoperability: The standardized structure of metadata enables interoperability between different organizations and systems. As environmental markets evolve and expand, this interoperability becomes crucial for sharing and validating information across platforms while maintaining data integrity and provenance.
Knowledge Graphs Creation & Advanced Queries: Well-structured metadata also enables the creation of knowledge graphs that reveal patterns and insights about ecological systems and interventions. These knowledge graphs support sophisticated queries that can track relationships between different types of data, claims, and evidence across the system. For example, users can explore connections between specific conservation practices and biodiversity outcomes or analyze the effectiveness of different verification approaches.
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