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json/api/json_view/index.md
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2026-10-21 10:31:00 +00:00

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# nlohmann::json_view
Defined in header `<nlohmann/json_view.hpp>`
```
using json_view = basic_json_view<json>;
```
This type is a [`basic_json_view`](https://json.nlohmann.me/api/basic_json_view/index.md) of a value of a [`json_document`](https://json.nlohmann.me/api/json_document/index.md).
## Examples
Example
The example below demonstrates how to use the type `nlohmann::json_view`.
```
#include <iostream>
#include <nlohmann/json_view.hpp>
int main()
{
std::cout << std::boolalpha;
// json_view is basic_json_view<nlohmann::json>: a read-only handle
// returned by json_document::root()
nlohmann::json_document doc = nlohmann::json_document::parse("[1, 2, 3]");
nlohmann::json_view v = doc.root();
std::cout << v.is_array() << ' ' << v.size() << '\n';
}
```
Output:
```
true 3
```
## See also
- [json_document](https://json.nlohmann.me/api/json_document/index.md) - the document type this view refers into
- [ordered_json_view](https://json.nlohmann.me/api/ordered_json_view/index.md) - the corresponding view for `ordered_json_document`
## Version history
Since version 3.13.0 unreleased.