> ## Documentation Index
> Fetch the complete documentation index at: https://syncmaven.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# Connection

The "Connection" defines how Syncmaven should connect to an external service, which typically involves a set of credentials required for this connection.

Connections are defined in the `connections` folder of a [Syncmaven project](/fundametals/project). Each connection is defined in a `.yml` or `.yaml`
file and can reference environment variables through the `${env.VARNAME`} syntax:

```yaml theme={null}
package:
  type: docker
  image: syncmaven/facebook:latest
credentials:
  accessToken: ${env.FACEBOOK_ADS_ACCESS_TOKEN}
  accountId: ${env.FACEBOOK_ADS_ACCOUNT_ID}
```

Each file must specify two nodes: `package`, which defines which package should be used, and `credentials`,
which contains the credentials.

At this moment, Syncmaven supports only Docker packages on dockerhub. `image` indicates the Docker image to be used.
Syncmaven talks to the Docker image through the [Syncmaven Protocol](/fundametals/protocol).

<Info> It is important not to store credentials in the connection file for security reasons. Refer to them through `${env.VARIABLE}` instead</Info>

The connection does not specify how the connected service should be used; it merely defines how Syncmaven should establish the connection. Connections are used in [syncs](/fundamentals/syncs)
to connect to destinations or enrichments.

# Connectors

Connector is a package that implements certain *connection*. At the moment, all connectors are packaged as Docker images
and follow the [Syncmaven Protocol](/fundametals/protocol).

# Destination Streams

Connector can implement [destination](/fundamentals/destination), [enrichment](/fundamentals/destination) of both.
Here we are talking about connectors that implement destination.

Destination defines one or more *Streams*. Each stream is a logical unit of data that can be written to the destination, and
represented by multiple rows sharing the same schema. In a way, stream is an equivalent of a table in a relational database.

For example, a connection to Hubspot defines a stream called `contacts` that represents a list of contacts in Hubspot. It
also might define a stream called `companies` that represents a list of companies in Hubspot.

To see all streams available for the destination, run the following command:

```bash theme={null}
syncmaven streams -f project/connection/destination.yml
```

<Info>
  *Why destination file is required, and I can't just get streams from docker image?*

  Streams depends on provided credentials. For example, different API keys might have access to different data in the same service.
</Info>