Options

Pass a delegate to UseMeziantouConventions to change the defaults:

builder.UseMeziantouConventions(options =>
{
    options.OpenApi.RoutePattern = "/swagger/{documentName}.json";
    options.Https.HstsEnabled = false;
    options.AntiForgery.Enabled = false;
    options.ForwardedHeaders.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
    options.ConfigureJsonOptions = json => json.WriteIndented = true;
    options.OpenTelemetry.ConfigureTracing = tracing => tracing.AddSource("MyCompany.*");
});

The delegate runs immediately, during the UseMeziantouConventions call, and the resulting MeziantouServiceDefaultsOptions is registered as a singleton. MapMeziantouDefaultEndpoints reads the same instance, so the options of the builder decide what the application maps.

All options

Option	Default	Effect
ValidateDependencyContainersOnStartup	`true`	Builds the service provider with `ValidateOnBuild` and `ValidateScopes`
`Https.Enabled`	`true`	Adds `UseHttpsRedirection`
`Https.HstsEnabled`	`true`	Adds `UseHsts` outside Development, when `Https.Enabled` is also `true`
`OpenApi.Enabled`	`true`	Registers OpenAPI and maps the document
`OpenApi.ConfigureOpenApi`	`null`	Configures the `OpenApiOptions` of the document
`OpenApi.RoutePattern`	`/openapi/{documentName}.json`	The route of the OpenAPI document
`OpenTelemetry.ConfigureLogging`	`null`	Configures the `OpenTelemetryLoggerOptions`, after the defaults
`OpenTelemetry.ConfigureMetrics`	`null`	Configures the `MeterProviderBuilder`, after the defaults
`OpenTelemetry.ConfigureTracing`	`null`	Configures the `TracerProviderBuilder`, after the defaults
ConfigureJsonOptions	`null`	Configures the `JsonSerializerOptions` of minimal APIs and controllers, after the conventions
`AntiForgery.Enabled`	`true`	Registers antiforgery and adds `UseAntiforgery`
`StaticAssets.Enabled`	`true`	Maps the static assets when the project has some
`ForwardedHeaders.ForwardedHeaders`	`XForwardedFor`, `XForwardedProto` and `XForwardedHost`	The headers processed by the forwarded headers middleware
`Caching.SetNoCacheWhenMissingCacheHeaders`	`true`	Adds the no-cache middleware

Common changes

The application runs behind a proxy that terminates TLS and forwards plain HTTP: keep Https.Enabled and make sure the proxy sends X-Forwarded-Proto, or set Https.Enabled = false when the proxy already redirects to HTTPS.
The application is reachable without a proxy: restrict ForwardedHeaders.ForwardedHeaders or set it to ForwardedHeaders.None; see Forwarded headers.
Your own ActivitySource or Meter has a name that does not start with Meziantou.: add it with ConfigureTracing (AddSource) or ConfigureMetrics (AddMeter). The source named after the application (IHostEnvironment.ApplicationName) is already traced.
An API without OpenAPI: set OpenApi.Enabled = false.
Long-lived cacheable responses everywhere: set Caching.SetNoCacheWhenMissingCacheHeaders = false, or set Cache-Control on those responses.
A registration that cannot be validated at startup, such as a service built from a factory that needs a running host: set ValidateDependencyContainersOnStartup = false. Keep it on otherwise: it turns a missing registration into an error on startup instead of on the first request that needs it.