This guide provides the basic structure for creating OpenSearch API documentation. It includes the various elements that we feel are most important to creating complete and useful API documentation, as well as description and examples where appropriate.
Terminology for API parameters varies in the software industry, where two or even three names may be used to label the same type of parameter. For consistency, we use the following nomenclature for parameters in our API documentation:
* *Path parameter* – "path parameter" and "URL parameter" are sometimes used synonymously. To avoid confusion, we use "path parameter" in this documentation.
* *Query parameter* – This parameter name is often used synonymously with "request parameter." We use "query parameter" to be consistent.
### General usage for code elements
When you describe any code element in a sentence, such as an API, a parameter, or a field, you can use the noun name.
*Example usage*:
The time field provides a timestamp for job completion.
When you provide an exact example with a value, you can use the code element in code font.
*Example usage*:
The response provides a value for `time_field`, such as “timestamp.”
The following sections describe the basic API documentation structure. Each section is discussed under its respective heading. Include only those elements appropriate to the API.
Provide an API name that describes its function, followed by a description of its top use case and any usage recommendations.
*Example function*: "Autocomplete queries"
Use sentence capitalization for the heading (for example, "Create or update mappings"). When you refer to the API operation, you can use lowercase with code font.
If there is a corresponding OpenSearch Dashboards feature, provide a “See also” link that references it.
*Example*: “To learn more about monitor findings, see [Document findings](https://opensearch.org/docs/latest/monitoring-plugins/alerting/monitors/#document-findings)."
If applicable, provide any caveats to its usage with a note or tip, as in the following example:
"If you use the Security plugin, make sure you have the appropriate permissions."
(To set this point in note-style format, follow the text on the next line with {: .note})
For relatively complex API calls that include path parameters, it's sometimes a good idea to provide an example so that users can visualize how the request is properly formed. This section is optional and includes examples that illustrate how the endpoint and path parameters fit together in the request. The following is an example of this section for the nodes stats API:
```json
GET /_nodes/stats
GET /_nodes/<node_id>/stats
GET /_nodes/stats/<metric>
GET /_nodes/<node_id>/stats/<metric>
GET /_nodes/stats/<metric>/<index_metric>
GET /_nodes/<node_id>/stats/<metric>/<index_metric>
While the API endpoint states a point of entry to a resource, the path parameter acts on the resource that precedes it. Path parameters come after the resource name in the URL.
Introduce what the path parameters can do at a high level. Provide a table with parameter names and descriptions. Include a table with the following columns:
In terms of placement, query parameters are always appended to the end of the URL and located to the right of the operator "?". Query parameters serve the purpose of modifying information to be retrieved from the resource.
Include a paragraph that describes how to use the query parameters with an example in code font. Include the query parameter operator "?" to delineate query parameters from path parameters.
For GET and DELETE APIs: Introduce what you can do with the optional parameters. Include a table with the same columns as the path parameter table.
Provide a sentence that describes what is shown in the example, followed by a cut-and-paste-ready API request in JSON format. Make sure that you test the request yourself in the Dashboards Dev Tools console to make sure it works. See the following examples.
