It's primarily used by Visual Studio to control how the application starts and what environment variables are set when debugging or running your functions locally.
The local.settings.json file stores app settings and settings used by local development tools. Settings in the local.settings.json file are used only when you're running your project locally.
The host.json metadata file contains configuration options that affect all functions in a function app instance. Configurations in host.json related to bindings are applied equally to each function in the function app.
The serviceDependencies.json file in an Azure Function is a JSON file that describes the Azure services that the function depends on. It can be used to configure local emulators for development and testing, and to automatically provision and configure Azure services when the function is deployed to production.
The serviceDependencies.json file is typically generated by Visual Studio when you connect your function to Azure services using the Connected Services dialog box. However, you can also edit the file manually.
The serviceDependencies.json file contains a dependencies object that lists the Azure services that the function depends on. Each dependency is represented by a JSON object that specifies the type of service and the connection string or other configuration information.
For example, the following serviceDependencies.json file defines a dependency on an Azure Storage account:
{ "dependencies": { "storage1": { "type": "Storage", "connectionString": "DefaultEndpointsProtocol=https;AccountName=;AccountKey=" } } }