Top-Level Settings

These settings configure the application identity, server binding, and configuration behavior.

Application Settings

{
  "ApplicationName": null,
  "EnvironmentName": "Production",
  "Urls": "http://localhost:8080",
  "StartupMessage": "Started in {time}, listening on {urls}, version {version}"
}

Settings Reference

Setting	Type	Default	Description
ApplicationName	string	null	Application identifier. Defaults to the top-level directory name if not set.
EnvironmentName	string	"Production"	Environment designation (Development, Staging, Production).
Urls	string	"http://localhost:8080"	Server listening URLs. Separate multiple URLs with semicolons.
StartupMessage	string	(see below)	Message displayed on startup. Supports placeholders.

Default StartupMessage: "Started in {time}, listening on {urls}, version {version}"

Urls Configuration

The Urls setting accepts multiple URLs separated by semicolons:

{
  "Urls": "http://localhost:8080;https://localhost:8443"
}

To listen on all interfaces:

{
  "Urls": "http://0.0.0.0:8080;https://0.0.0.0:8443"
}

Startup Message Placeholders

Customize the startup message with these placeholders:

Placeholder	Description
{time}	Startup time
{urls}	Listening URLs
{version}	Application version
{environment}	Environment name (from EnvironmentName)
{application}	Application name (from ApplicationName)

Example:

{
  "StartupMessage": "Started in {time}, listening on {urls}, version {version}, env: {environment}"
}

Config Section

The Config section controls how the configuration file itself is processed.

{
  "Config": {
    "ExposeAsEndpoint": null,
    "AddEnvironmentVariables": false,
    "ParseEnvironmentVariables": true
  }
}

Settings Reference

Setting	Type	Default	Description
ExposeAsEndpoint	string	null	Expose current configuration to an endpoint for debugging. Set to a path like "/config" to enable. Passwords in connection strings are not exposed.
AddEnvironmentVariables	bool	false	Allow environment variables to override configuration settings.
ParseEnvironmentVariables	bool	true	Parse {ENV_VAR_NAME} placeholders in config values and replace with environment variable values.

Environment Variable Override

When AddEnvironmentVariables is true, environment variables can override any configuration setting. Use double underscores for nested keys:

# Override ConnectionStrings.Default
export ConnectionStrings__Default="Host=production-server;..."

# Override NpgsqlRest.UrlPathPrefix
export NpgsqlRest__UrlPathPrefix="/v2/api"

Environment Variable Parsing

When ParseEnvironmentVariables is true (default), you can use {ENV_VAR} syntax anywhere in configuration values:

{
  "ConnectionStrings": {
    "Default": "Host={PGHOST};Port={PGPORT};Database={PGDATABASE};Username={PGUSER};Password={PGPASSWORD}"
  }
}

This allows sensitive values to be kept in environment variables rather than in the configuration file.

Exposing Configuration

For debugging purposes, you can expose the current configuration as an endpoint:

{
  "Config": {
    "ExposeAsEndpoint": "/config"
  }
}

This creates a GET /config endpoint that returns the current configuration as JSON. Passwords in connection strings are automatically redacted.

Related

• Comment Annotations Guide - How annotations work
• Configuration Guide - How configuration sources work

Next Steps

• Connection Settings - Database connection strings
• Server & SSL - Kestrel and HTTPS configuration