> For the complete documentation index, see [llms.txt](https://docs.simple.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.simple.org/engineering/android/headers-sent-from-the-app.md).

# Headers sent from the app

| Key                 | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Example Value                          |
| ------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------- |
| `X-APP-VERSION`     | The build version string of the Android client. This is generally auto-generated for every build by the continuous deployment service.                                                                                                                                                                                                                                                                                                                                                                                                        | `2019-08-26-5229`                      |
| `Accept-Language`   | <p>The current language selected by the user. Currently, this is the device language. In the future, when we build out the in-app language switcher, will be the language selected by the user. See the official <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language">docs</a> for more information.</p><p></p><p>Note: this is only a hint to the server so that they can select strings and set the response language correctly. The response is not verified by the app to be in the selected language.</p> | `en-US`, `hi-IN`                       |
| `X-TIMEZONE-ID`     | The timezone set by the user on the device. Will be a standard timezone ID.                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | `Asia/Kolkata`,`Etc/GMT-14`            |
| `X-TIMEZONE-OFFSET` | <p>This will be the raw offset (in seconds) that the current user is from UTC. This value will be <strong>inclusive</strong> of adjustments like <a href="https://en.wikipedia.org/wiki/Daylight_saving_time">DST</a>.</p><p></p><p>This is what the server should use if the server needs to find the calendar date a request is being sent from from UTC timestamps. </p>                                                                                                                                                                   | `3600`,`-3600`                         |
| `X-USER-ID`         | This is the ID of the logged in user. This field will be absent if the user has not logged in yet.                                                                                                                                                                                                                                                                                                                                                                                                                                            | `30b9c537-4a53-4d92-bf0f-cefed3f5e63e` |
| `X-FACILITY-ID`     | This is the facility ID which is selected by the current logged in user. This field will be absent if the user has not logged in yet.                                                                                                                                                                                                                                                                                                                                                                                                         | `7fc136a1-5ea7-40c7-8154-452a35481340` |