# Updating Config Files

Advance users may wish to further configure the application using documented environment variables.

## Environment Variables

Environment variables can be configured depending on your deployment.

### Docker

#### Naming Convention

 SupportPal specific environment variables, those documented as configuration items, should be prefixed with `SUPPORTPAL_`. These environment variables will be written to an `.env` file within the SupportPal installation directory at container startup.

The names of any other environment variable should not be prefixed.

#### Usage

Environment variables should be written to the `environment` section within `docker-compose.override.yml`.

docker-compose.override.yml

```

version: '3.8'

services:
    supportpal:
        environment:
            HTTPS_ENABLED: 1
            EMAIL_ADDRESS: "my@email.com"
            DOMAIN_NAMES: "help.domain.com, support.domain.com"
            SUPPORTPAL_TRUSTED_PROXY_IPS: "152.164.0.10,127.0.0.1"
            SUPPORTPAL_EMAIL_THROTTLE_MAX_REQUESTS: 100

```

### Other Deployments

 Create a `.env` file in the installation directory. For full usage information, refer to the [Dotenv documentation](https://github.com/vlucas/phpdotenv#usage).

.env

```

EMAIL_THROTTLE_MAX_REQUESTS=100

```

## Configuration Options

#### [App Configuration](App+Configuration)

 The application configuration can be further fine-tuned outside the operator panel. These items exist as environment variables as their default values are OK for most users, but allow advanced users to better control the application.

#### [Broadcasting Configuration](Broadcasting+Configuration)

 By default, the application uses XHR short polling to broadcast events that happen. XHR polling works out of the box without any additional configuration but can quickly become resource intensive and increase bandwidth usage as application usage grows. We recommend to use web sockets instead.

#### [Cloud Storage](Cloud+Storage)

 By default application data is stored locally in the `storage/app/` directory within your installation directory. In high availability deployments, it's necessary for some of these files such as ticket attachments to be available to all application servers and this can be achieved using cloud storage.

#### [Mail Security Policy](Mail+Security+Policy)

 The use of merge fields in the operator panel is regulated by a strict policy for security reasons. This restricts what is possible for your help desk staff to do in terms of twig code and helps to keep the server secure.

#### [Redis](Redis)

 In standalone installations the application uses a file-based storage for cache and session data. It allows the application to be used out of the box without any additional configuration. However, as application usage grows IO access can become a bottleneck. Redis is a great alternative which offers an open source, fast, in-memory, data store.

#### [Requests](Requests)

 This page describes configuration items to tweak how inbound and outbound requests are handled within the application.

#### [Search](Search)

 SupportPal currently supports three search engines, the built-in MySQL full-text engine, Meilisearch, and Algolia - a cloud search engine.