title	description	ms.date	ms.topic
Aspire AppHost configuration	Learn about the Aspire AppHost configuration options.	04/15/2025	reference

AppHost configuration

The AppHost project configures and starts your distributed application (xref:Aspire.Hosting.DistributedApplication). When a DistributedApplication runs it reads configuration from the AppHost. Configuration is loaded from environment variables that are set on the AppHost and xref:Aspire.Hosting.DistributedApplicationOptions.

Configuration includes:

Settings for hosting the resource service, such as the address and authentication options.
Settings used to start the Aspire dashboard, such the dashboard's frontend and OpenTelemetry Protocol (OTLP) addresses.
Internal settings that Aspire uses to run the AppHost. These are set internally but can be accessed by integrations that extend Aspire.

AppHost configuration is provided by the AppHost launch profile. The AppHost has a launch settings file call launchSettings.json which has a list of launch profiles. Each launch profile is a collection of related options which defines how you would like dotnet to start your application.

{
  "$schema": "https://json.schemastore.org/launchsettings.json",
  "profiles": {
    "https": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "applicationUrl": "https://localhost:17134;http://localhost:15170",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        "DOTNET_ENVIRONMENT": "Development",
        "ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL": "https://localhost:21030",
        "ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL": "https://localhost:22057"
      }
    }
  }
}

The preceding launch settings file:

Has one launch profile named https.
Configures an Aspire AppHost project:
- The applicationUrl property configures the dashboard launch address (ASPNETCORE_URLS).
- Environment variables such as ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL and ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL are set on the AppHost.

For more information, see Aspire and launch profiles.

Note

Configuration described on this page is for Aspire AppHost project. To configure the standalone dashboard, see dashboard configuration.

Common configuration

Option	Default value	Description
`ASPIRE_ALLOW_UNSECURED_TRANSPORT`	`false`	Allows communication with the AppHost without https. `ASPNETCORE_URLS` (dashboard address) and `ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL` (AppHost resource service address) must be secured with HTTPS unless true.
`ASPIRE_CONTAINER_RUNTIME`	`docker`	Allows the user of alternative container runtimes for resources backed by containers. Possible values are `docker` (default) or `podman`. See Setup and tooling overview for more details.
`ASPIRE_VERSION_CHECK_DISABLED`	`false`	When set to `true`, Aspire doesn't check for newer versions on startup.

Aspire version update notifications

When an Aspire app starts, it checks if a newer version of Aspire is available on NuGet. If a new version is found, a notification appears in the dashboard with the latest version number, a link to upgrade instructions, and button to ignore that version in the future.

:::image type="content" source="../whats-new/media/dashboard-update-notification.png" lightbox="../whats-new/media/dashboard-update-notification.png" alt-text="Screenshot of dashboard showing a version update notification with upgrade options.":::

The version check runs only when:

The dashboard is enabled (interaction service is available).
At least 2 days have passed since the last check.
The check hasn't been disabled via the ASPIRE_VERSION_CHECK_DISABLED configuration setting.
The app is not running in publish mode.

Updates are manual. You need to edit your project file to upgrade the Aspire SDK and package versions.

Resource service

A resource service is hosted by the AppHost. The resource service is used by the dashboard to fetch information about resources which are being orchestrated by Aspire.

Option	Default value	Description
`ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL`	`null`	Configures the address of the resource service hosted by the AppHost. Automatically generated with launchSettings.json to have a random port on localhost. For example, `https://localhost:17037`.
`ASPIRE_DASHBOARD_RESOURCESERVICE_APIKEY`	Automatically generated 128-bit entropy token.	The API key used to authenticate requests made to the AppHost's resource service. The API key is required if the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with `ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS`.

Dashboard

By default, the dashboard is automatically started by the AppHost. The dashboard supports its own set of configuration, and some settings can be configured from the AppHost.

Option	Default value	Description
`ASPNETCORE_URLS`	`null`	Dashboard address. Must be `https` unless `ASPIRE_ALLOW_UNSECURED_TRANSPORT` or `DistributedApplicationOptions.AllowUnsecuredTransport` is true. Automatically generated with launchSettings.json to have a random port on localhost. The value in launch settings is set on the `applicationUrls` property.
`ASPNETCORE_ENVIRONMENT`	`Production`	Configures the environment the dashboard runs as. For more information, see Use multiple environments in ASP.NET Core.
`ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL`	`http://localhost:18889` if no gRPC endpoint is configured.	Configures the dashboard OTLP gRPC address. Used by the dashboard to receive telemetry over OTLP. Set on resources as the `OTEL_EXPORTER_OTLP_ENDPOINT` env var. The `OTEL_EXPORTER_OTLP_PROTOCOL` env var is `grpc`. Automatically generated with launchSettings.json to have a random port on localhost.
`ASPIRE_DASHBOARD_OTLP_HTTP_ENDPOINT_URL`	`null`	Configures the dashboard OTLP HTTP address. Used by the dashboard to receive telemetry over OTLP. If only `ASPIRE_DASHBOARD_OTLP_HTTP_ENDPOINT_URL` is configured then it is set on resources as the `OTEL_EXPORTER_OTLP_ENDPOINT` env var. The `OTEL_EXPORTER_OTLP_PROTOCOL` env var is `http/protobuf`.
`ASPIRE_DASHBOARD_CORS_ALLOWED_ORIGINS`	`null`	Overrides the CORS allowed origins configured in the dashboard. This setting replaces the default behavior of calculating allowed origins based on resource endpoints.
`ASPIRE_DASHBOARD_FRONTEND_BROWSERTOKEN`	Automatically generated 128-bit entropy token.	Configures the frontend browser token. This is the value that must be entered to access the dashboard when the auth mode is BrowserToken. If no browser token is specified then a new token is generated each time the AppHost is launched.
`ASPIRE_DASHBOARD_TELEMETRY_OPTOUT`	`false`	Configures the dashboard to never send usage telemetry.
`ASPIRE_DASHBOARD_AI_DISABLED`	`false`	GitHub Copilot in the dashboard is available when the AppHost is launched by a supported IDE. When set to `true` Copilot is disabled in the dashboard and no Copilot UI is visible.
`ASPIRE_DASHBOARD_FORWARDEDHEADERS_ENABLED`	`false`	Enables the Forwarded headers middleware that replaces the scheme and host values on the Request context with the values coming from the `X-Forwarded-Proto` and `X-Forwarded-Host` headers.

Internal

Internal settings are used by the AppHost and integrations. Internal settings aren't designed to be configured directly.

Option	Default value	Description
`AppHost:Directory`	The content root if there's no project.	Directory of the project where the AppHost is located. Accessible from the xref:Aspire.Hosting.IDistributedApplicationBuilder.AppHostDirectory?displayProperty=nameWithType.
`AppHost:Path`	The directory combined with the application name.	The path to the AppHost. It combines the directory with the application name.
`AppHost:Sha256`	It is created from the AppHost name when the AppHost is in publish mode. Otherwise it is created from the AppHost path.	Hex encoded hash for the current application. The hash is based on the location of the app on the current machine so it is stable between launches of the AppHost.
`AppHost:OtlpApiKey`	Automatically generated 128-bit entropy token.	The API key used to authenticate requests sent to the dashboard OTLP service. The value is present if needed: the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with `ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS`.
`AppHost:BrowserToken`	Automatically generated 128-bit entropy token.	The browser token used to authenticate browsing to the dashboard when it is launched by the AppHost. The browser token can be set by `ASPIRE_DASHBOARD_FRONTEND_BROWSERTOKEN`. The value is present if needed: the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with `ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS`.
`AppHost:ResourceService:AuthMode`	`ApiKey`. If `ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS` is true then the value is `Unsecured`.	The authentication mode used to access the resource service. The value is present if needed: the AppHost is in run mode and the dashboard isn't disabled.
`AppHost:ResourceService:ApiKey`	Automatically generated 128-bit entropy token.	The API key used to authenticate requests made to the AppHost's resource service. The API key can be set by `ASPIRE_DASHBOARD_RESOURCESERVICE_APIKEY`. The value is present if needed: the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with `ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS`.

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