# Anchored Metadata

For credit classes, projects, and credit batches, the `metadata` field in the ecocredit module holds an IRI that points to an off-chain JSON-LD document. Metadata for these entities is accessed the same way:

1. **Query the Ledger** (via gRPC, REST, or CLI) to retrieve the entity's metadata IRI
2. **Resolve the IRI** using the Metadata Graph API to retrieve the full JSON-LD document
3. **Interpret the JSON-LD** as linked data describing the entity's attributes, relationships, and supporting documents

{% hint style="info" %}
The Regen Network Framework Working Group's is currently finalizing a RDF standardization for credit classes, project, credit batches and more. Once complete **all metadata documents will share a standardized structure**, making them predictable, machine-readable, and interoperable across applications.
{% endhint %}

### Retrieving Metadata IRIs from the Ledger

Each entity stores its metadata reference in a `metadata` field within the ecocredit module. Ledger queries return a string like:

```
regen:13toVh9VgHfMJUDXSFTMQiDwRtiWQvhyeBpZe3jYpGMRnkZZB7jQyN8.rdf
```

This IRI is a deterministic, content-addressed identifier for the full metadata document.

### Resolving IRIs via the Metadata Graph API

Use the Metadata Graph API to resolve any IRI:

```
GET https://api.regen.network/data/v2/metadata-graph/{iri}
```

The API automatically retrieves content from IPFS, HTTPS endpoints, or other configured resolvers and returns a JSON-LD document containing the complete semantic structure: context, types, relationships, and links to supporting evidence.

For full API specifications, see the [Metadata Graph API Swagger docs](https://api.regen.network/swagger/).

### JSON-LD Response Examples

#### Credit Class Metadata

Credit class metadata describes the protocol itself—methodology, eligible activities, impact categories, and governance structure.

**Request:**

```
GET https://api.regen.network/data/v2/metadata-graph/regen:...class-iri....rdf
```

**Response (excerpt):**

json

{% code overflow="wrap" expandable="true" %}

```json
{
  "@type": "regen:USS-CreditClass",
  "@context": {
    "regen": "https://schema.regen.network#",
    "schema": "http://schema.org/",
    "schema:url": { "@type": "schema:URL" },
    "regen:coBenefits": { "@container": "@list" },
    "regen:creditingTerm": { "@type": "schema:Duration" }
  },
  "schema:name": "Biodiversity Credit Protocol for Umbrella Species Stewardship",
  "schema:url": "https://www.registry.regen.network/crediting-protocols/era-brazil",
  "schema:description": "The Biodiversity Crediting Protocol for Umbrella Species Stewardship (USS) provides...",
  "regen:creditingTerm": "P5Y",
  "regen:ecosystemType": ["Terrestrial"],
  "regen:primaryImpact": {
    "@id": "regen:Improved-Biodiversity",
    "schema:name": "Improved Biodiversity",
    "regen:SDGs": [
      { "@id": "regen:15LifeOnLand" },
      { "@id": "regen:13ClimateAction" }
    ]
  },
  "regen:eligibleActivities": [
    "Umbrella Species Conservation",
    "Ecosystem Restoration",
    "Ecotourism"
  ]
}
```

{% endcode %}

**Typical fields:** protocol name and description, crediting term, ecosystem types, primary impact with SDG mappings, eligible activities, applicable regions, and links to methodology documents.

***

#### Project Metadata

Project metadata describes the specific implementation—location, stakeholders, ecosystem characteristics, and activities.

**Request:**

```
GET https://api.regen.network/data/v2/metadata-graph/regen:...project-iri....rdf
```

**Response (excerpt):**

json

{% code overflow="wrap" expandable="true" %}

```json
{
  "@id": "https://app.regen.network/project/USS01-001",
  "@type": "regen:USS01-Project",
  "@context": {
    "regen": "https://schema.regen.network#",
    "schema": "http://schema.org/",
    "geojson": "https://purl.org/geojson/vocab#",
    "schema:location": {
      "@context": {
        "@vocab": "https://purl.org/geojson/vocab#",
        "coordinates": { "@container": "@list" }
      }
    },
    "regen:coBenefits": { "@container": "@list" }
  },
  "schema:name": "Jaguar Stewardship in the Pantanal Conservation Network",
  "schema:location": {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [-57.489822, -18.040224]
    },
    "place_name": "Serra do Amolar, Corumbá, Mato Grosso do Sul, Brazil"
  },
  "schema:description": "The Instituto Homem Pantaneiro (IHP) is an NGO dedicated to preserving the Brazilian Pantanal biome...",
  "regen:projectSize": {
    "qudt:unit": "unit:HA",
    "qudt:numericValue": 40613
  },
  "regen:ecosystemType": ["Tropical Wetlands"],
  "regen:projectDeveloper": {
    "@type": "regen:Organization",
    "schema:name": "ERA Brazil"
  },
  "regen:projectOperator": {
    "@type": "regen:Organization",
    "schema:name": "Instituto Homem Pantaneiro"
  }
}
```

{% endcode %}

**Typical fields:** name and description, geographic location (GeoJSON), project size, ecosystem type, project developer/operator/monitor/verifier, co-benefits, activities, media assets, and start/end dates.

***

#### Credit Batch Metadata

Credit batch metadata documents the issuance event—monitoring reports, verification reports, and supporting evidence.

**Request:**

```
GET https://api.regen.network/data/v2/metadata-graph/regen:...batch-iri....rdf
```

**Response (excerpt):**

json

{% code overflow="wrap" expandable="true" %}

```json
{
  "@type": "regen:USS01-CreditBatch",
  "@context": {
    "regen": "https://framework.regen.network",
    "schema": "http://schema.org/",
    "schema:url": { "@type": "schema:URL" },
    "regen:monitoringReport": { "@container": "@list" },
    "regen:verificationReport": { "@container": "@list" }
  },
  "regen:registryAgent": {
    "schema:name": "Regen Network Development, PBC",
    "schema:url": "https://registry.regen.network"
  },
  "regen:projectVerifier": {
    "schema:name": "Verifit",
    "schema:url": "https://verifit.com.co/"
  },
  "regen:monitoringReport": [
    {
      "schema:name": "ERABrazil Monitoring Report (2021-2023)",
      "schema:url": "https://regen-registry.s3.us-east-1.amazonaws.com/...Monitoring+Report...",
      "regen:dataIRI": "regen:114EfLg2Xns4F5SCWQZ1f2EK1RqWNrqvQMTgPsFcvMBdwJNKGt2A.pdf"
    }
  ],
  "regen:verificationReport": [
    {
      "schema:name": "Verifit Validation & Verification Report (Jan 2025)",
      "schema:url": "https://regen-registry.s3.us-east-1.amazonaws.com/...Verification+Report...",
      "regen:dataIRI": "regen:114ZqehBLYAzaroF7nHSYwEMTzPZW6isEY4gr2myxEhbFyUNWh31.pdf"
    }
  ]
}
```

{% endcode %}

**Typical fields:** registry agent, project verifier, monitoring reports with anchored data IRIs, verification reports, supplemental materials, and links to PDFs and evidence documents.

***

### Upcoming Standardization

The Framework Working Group is finalizing unified LinkML-backed metadata schemas for credit classes, projects, credit batches, evidence, claims, and methodologies.

Once adopted:

* All JSON-LD documents will share consistent structures across entity types
* Developers can reliably parse metadata using shared vocabularies
* New capabilities (SPARQL queries, schema validation, graph navigation) will work seamlessly across the ecosystem