# Browser

LLMS index: [llms.txt](/llms.txt)

---

## Browser

**Status:** ![Development](https://img.shields.io/badge/-development-blue)

**type:** `browser`

**Description:** The web browser in which the application represented by the resource is running. The `browser.*` attributes MUST be used only for resources that represent applications running in a web browser (regardless of whether running on a mobile or desktop device).

> [!warning]
> This entity definition contains attributes without a role.
> Stable Entities MUST NOT have attributes without a defined role.

**Attributes:**

| Role | Key | Stability | [Requirement Level](/docs/specs/semconv/general/attribute-requirement-level/) | Value Type | Description | Example Values |
| --- | --- | --- | --- | --- | --- | --- |
| Other | [`browser.brands`](/docs/specs/semconv/registry/attributes/browser.md) | ![Development](https://img.shields.io/badge/-development-blue) | `Recommended` | string[] | Array of brand name and version separated by a space [1] | `[" Not A;Brand 99", "Chromium 99", "Chrome 99"]` |
| Other | [`browser.language`](/docs/specs/semconv/registry/attributes/browser.md) | ![Development](https://img.shields.io/badge/-development-blue) | `Recommended` | string | Preferred language of the user using the browser [2] | `en`; `en-US`; `fr`; `fr-FR` |
| Other | [`browser.mobile`](/docs/specs/semconv/registry/attributes/browser.md) | ![Development](https://img.shields.io/badge/-development-blue) | `Recommended` | boolean | A boolean that is true if the browser is running on a mobile device [3] | |
| Other | [`browser.platform`](/docs/specs/semconv/registry/attributes/browser.md) | ![Development](https://img.shields.io/badge/-development-blue) | `Recommended` | string | The platform on which the browser is running [4] | `Windows`; `macOS`; `Android` |
| Other | [`user_agent.original`](/docs/specs/semconv/registry/attributes/user-agent.md) | ![Stable](https://img.shields.io/badge/-stable-lightgreen) | `Recommended` | string | Full user-agent string provided by the browser [5] | `Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.54 Safari/537.36` |

**[1] `browser.brands`:** This value is intended to be taken from the [UA client hints API](https://wicg.github.io/ua-client-hints/#interface) (`navigator.userAgentData.brands`).

**[2] `browser.language`:** This value is intended to be taken from the Navigator API `navigator.language`.

**[3] `browser.mobile`:** This value is intended to be taken from the [UA client hints API](https://wicg.github.io/ua-client-hints/#interface) (`navigator.userAgentData.mobile`). If unavailable, this attribute SHOULD be left unset.

**[4] `browser.platform`:** This value is intended to be taken from the [UA client hints API](https://wicg.github.io/ua-client-hints/#interface) (`navigator.userAgentData.platform`). If unavailable, the legacy `navigator.platform` API SHOULD NOT be used instead and this attribute SHOULD be left unset in order for the values to be consistent.
The list of possible values is defined in the [W3C User-Agent Client Hints specification](https://wicg.github.io/ua-client-hints/#sec-ch-ua-platform). Note that some (but not all) of these values can overlap with values in the [`os.type` and `os.name` attributes](./os.md). However, for consistency, the values in the `browser.platform` attribute should capture the exact value that the user agent provides.

**[5] `user_agent.original`:** The user-agent value SHOULD be provided only from browsers that do not have a mechanism to retrieve brands and platform individually from the User-Agent Client Hints API. To retrieve the value, the legacy `navigator.userAgent` API can be used.