# Data Transfer Objects

Data transfer objects, or DTOs, are objects used to wrap resource definitions in request/response objects along with additional information.

In a response body, you should return a JSON object, not an array, as a top level data structure to support future extensibility. This would allow you to extend your response and, for example, add a server side pagination attribute.

**Bad response body**

```
[
  { "id": "1", "name": "Einar"   },
  { "id": "2", "name": "Erlendur"},
  { "id": "3", "name": "Valdimar"}
]
```

**Good response body**

```
{
  "users":[
    { "id": "1001", "name": "Einar"},
    { "id": "1002", "name": "Erlendur"},
    { "id": "1003", "name": "Valdimar"},
  ]
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.devland.is/technical-overview/api-design-guide/data-transfer-objects.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.