> For the complete documentation index, see [llms.txt](https://tri.gitbook.io/tri-doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://tri.gitbook.io/tri-doc/carbon-credit/d-mrv-methodologies.md).

# D-MRV Methodologies

### Carbon Credit

<mark style="color:blue;">`GET`</mark> <https://sandbox.triangle.digital/api/v2/d\\_mrv\\_methodologies>

The methodologies offered for linking to a Carbon Credit project — the same set, with the same registry names, that the Carbon Credit form offers in "Choose or Create a Registry". A methodology whose form belongs to no company is not offered. Each entry carries its identifier and its version, because a methodology is unique per name AND version — two versions of one protocol are two records with the same name.

This endpoint lists the methodologies of every company, while [Get Methodologies List](/tri-doc/methodology-or-protocol/get-methodologies-list.md) returns the methodologies of your own account, with their registry answers and documents. Both are valid sources of `methodology_id`.

**Headers**

<table data-full-width="true"><thead><tr><th>Name</th><th>Value</th></tr></thead><tbody><tr><td>Content-Type</td><td><code>application/json</code></td></tr></tbody></table>

**Query parameters**

<table data-full-width="true" data-search="false"><thead><tr><th width="200">Name</th><th width="110">Type</th><th>Description</th><th width="260">Example</th></tr></thead><tbody><tr><td><code>hash</code></td><td>string</td><td><strong>Required.</strong> API key.</td><td>fk5f0iuy-rr06-j4x3-i75b-fy2s67s4ilo1</td></tr></tbody></table>

**Response fields**

<table data-full-width="true" data-search="false"><thead><tr><th width="300">Field</th><th width="110">Type</th><th>Description</th></tr></thead><tbody><tr><td><code>message</code></td><td>string</td><td>Human-readable result of the call.</td></tr><tr><td><code>success</code></td><td>boolean</td><td>Whether the methodologies were retrieved; a refused call answers HTTP 400.</td></tr><tr><td><code>data.d_mrv_methodologies[].id</code></td><td>integer</td><td>The methodology identifier is one value under three names: <code>form_id</code> in the <a href="/tri-doc/methodology-or-protocol.md">Methodology | Protocol</a> section, <code>id</code> in <a href="/tri-doc/carbon-credit/d-mrv-methodologies.md">D-MRV Methodologies</a>, and <code>methodology_id</code> when a project links it via <a href="/tri-doc/carbon-credit/add-project.md">Add Project</a>.</td></tr><tr><td><code>data.d_mrv_methodologies[].name</code></td><td>string</td><td>Name of the methodology. <code>null</code> when the methodology has not been named yet — <code>display</code> then falls back to the company name or to <code>Methodology #&#x3C;id></code>.</td></tr><tr><td><code>data.d_mrv_methodologies[].version</code></td><td>string</td><td>Version of the methodology. <code>null</code> when it has none.</td></tr><tr><td><code>data.d_mrv_methodologies[].display</code></td><td>string</td><td>Name and version joined for display, in the form <code>Name - version</code>; the name alone when there is no version.</td></tr><tr><td><code>data.d_mrv_methodologies[].registry</code></td><td>string</td><td>Registry of the methodology, always filled and always the same value the Carbon Credit form shows: the Name Of The Registry when the methodology form says it is part of a carbon credit registry, otherwise the name of the company that owns it. A display label — link an existing methodology by <code>id</code>, not by this name.</td></tr><tr><td><code>operations_count</code></td><td>integer</td><td>Operations counted for this call in the API usage accounting.</td></tr></tbody></table>

**Response**

{% tabs %}
{% tab title="200" %}
{% code fullWidth="false" %}

```json
{
    "message": "Data received successfully.",
    "success": true,
    "data": {
        "d_mrv_methodologies": [
            {
                "id": 74,
                "name": "Blue Carbon Protocol",
                "version": "2.2",
                "display": "Blue Carbon Protocol - 2.2",
                "registry": "BCarbon"
            },
            {
                "id": 63,
                "name": "CDM AMS I.D.",
                "version": null,
                "display": "CDM AMS I.D.",
                "registry": "Nexora Labs"
            }
        ]
    },
    "operations_count": 1
}
```

{% endcode %}
{% endtab %}

{% tab title="400" %}
Happens when `hash` is missing or does not match an active API key; no data is returned.

```json
{
    "message": "Error! No such hash.",
    "success": false
}
```

{% endtab %}
{% endtabs %}