> 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/methodology-or-protocol.md).

# Methodology | Protocol

This section covers registering a D-MRV methodology or protocol with its registry answers, contacts and documents, reading one back, listing the methodologies your account can see, and how a Carbon Credit project links such a methodology.

**Authorization.** Every call carries the `hash` parameter with your API key.

**Answers.** The endpoints answer with the `{message, success, data, operations_count}` envelope; a refused call answers HTTP 400 with `success: false`.

**Name and version.** A methodology is unique per its `methodology_name` and `methodology_version_number`, so two versions of one protocol are two records. Name and version joined for display, in the form `Name - version`; the name alone when there is no version. The pair is also what a Carbon Credit project resolves when it links a methodology by name.

**The registry.** A company may have several registries. Each methodology belongs to one of them, set by `registry_questionnaire_id`; the registries of your company are listed by [Get Registries List](/tri-doc/methodology-or-protocol/get-registries-list.md). The name of the registry is returned as `registry_name`. A registry created from the Carbon Credit form lands here as a methodology of its own — see [Add Project](/tri-doc/carbon-credit/add-project.md) for how a project selects its Registry.

**Blocks of rows.** A block is one field, an array of objects. A block the request carries replaces the stored block whole; a block the request does not mention is left as it is; an empty array clears it. Contact blocks take up to 20 rows; the Data Room rows take up to 100. Documents travel as rows of `data_room`; links travel in the link blocks.

**Endpoints**

<table data-full-width="true"><thead><tr><th width="340">Endpoint</th><th>What it does</th></tr></thead><tbody><tr><td><a href="/tri-doc/methodology-or-protocol/add-methodology.md">Add Methodology</a></td><td>Registers a methodology, with its registry answers, contacts and documents.</td></tr><tr><td><a href="/tri-doc/methodology-or-protocol/update-methodology.md">Update Methodology</a></td><td>Changes any field of a methodology, contacts and documents included.</td></tr><tr><td><a href="/tri-doc/methodology-or-protocol/get-methodologies-list.md">Get Methodologies List</a></td><td>Lists the methodologies your account can see, with their versions.</td></tr><tr><td><a href="/tri-doc/methodology-or-protocol/view-methodology.md">View Methodology</a></td><td>Returns one methodology in full.</td></tr><tr><td><a href="/tri-doc/methodology-or-protocol/get-registries-list.md">Get Registries List</a></td><td>Returns the registries of your company.</td></tr></tbody></table>