# Hosting and client relationship

The division between modeling a dependency in the AppHost and connecting to that dependency inside an application.

Also known as: The relationship, integration relationship

A hosting integration and a client integration serve different layers of the same application:

1. The AppHost uses a hosting integration to model the service, such as a PostgreSQL server and database.
2. A resource reference passes the database's connection information to the consuming API.
3. The API uses a client integration or its usual database library to read that configuration and connect.

For .NET, `Aspire.Hosting.PostgreSQL` belongs in the AppHost and `Aspire.Npgsql` belongs in the application. A Python or JavaScript API can consume the same configuration with its own PostgreSQL client; it does not need a .NET client package.

## Practical example

The AppHost provisions connection information for a named database; the API uses its database client to open the connection.

## Learn more

- [Choose hosting and client integrations](https://aspire.dev/integrations/overview/)

## Related terms

- [Client integration](https://aspire.dev/hub/glossary/client-integration/)

- [Hosting integration](https://aspire.dev/hub/glossary/hosting-integration/)

- [WithReference](https://aspire.dev/hub/glossary/withreference/)