you can use HttpContext object to access endpoint and metadata like attributes.

        var endpoint = context.GetEndpoint();
        var IsAllowAnonymous = endpoint != null && endpoint.Metadata.Any(x=>x.GetType()==typeof(AllowAnonymousAttribute));

then add a conditional in your check to skip.

Note: you should place your middleware after Routing middleware to use GetEndpoint extension method. if your middleware place before Routing middleware GetEndpoint extension method return null

app.UseRouting();

app.UseMiddleware<ApiKeyMiddleware>();

you can use HttpContext object to access endpoint and metadata like attributes.

var endpoint = context.GetEndpoint();
var isAllowAnonymous = endpoint?.Metadata.Any(x => x.GetType() == typeof(AllowAnonymousAttribute));

then add a conditional in your check to skip.

if (isAllowAnonymous == true)
{
    await _next(context);
    return;
}

Note: you should place your middleware after Routing middleware to use GetEndpoint extension method. if your middleware place before Routing middleware GetEndpoint extension method return null

app.UseRouting();

app.UseMiddleware<ApiKeyMiddleware>();