> For the complete documentation index, see [llms.txt](https://vostok.gitbook.io/configuration/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vostok.gitbook.io/configuration/sources/environment-variables-source.md).

# Environment variables source

**Location**: [main sources module](/configuration/modules/sources.md).

[**EnvironmentVariablesSource**](https://github.com/vostok/configuration.sources/blob/master/Vostok.Configuration.Sources/Environment/EnvironmentVariablesSource.cs) converts process environment variables into settings nodes.

```
var source = new EnvironmentVariablesSource();
```

Keys with dots, colons and double underscores are treated as hierarchical and get split into segments:

```
throttling.capacity=50 --> { "throttling": { "capacity": "50" } }
throttling:capacity=50 --> { "throttling": { "capacity": "50" } }
throttling__capacity=50 --> { "throttling": { "capacity": "50" } }
```

This source is static and never issues data updates.

### Related pages

{% content-ref url="/pages/-M6UQMklC2EtQ\_nAUDjI" %}
[Configuration sources](/configuration/concepts-and-basics/configuration-sources.md)
{% endcontent-ref %}