diff --git a/cmd/karma/views_test.go b/cmd/karma/views_test.go
index 1860cc6d4..a38a134ec 100644
--- a/cmd/karma/views_test.go
+++ b/cmd/karma/views_test.go
@@ -769,3 +769,52 @@ func TestCORS(t *testing.T) {
 		t.Errorf("Invalid Access-Control-Allow-Origin value %q, expected 'foo.example.com'", resp.Header().Get("Access-Control-Allow-Origin"))
 	}
 }
+
+func TestEmptySettings(t *testing.T) {
+	mockConfig()
+	r := ginTestEngine()
+	req := httptest.NewRequest("GET", "/alerts.json", nil)
+
+	resp := httptest.NewRecorder()
+	r.ServeHTTP(resp, req)
+	if resp.Code != http.StatusOK {
+		t.Errorf("GET /alerts.json returned status %d", resp.Code)
+	}
+	ur := models.AlertsResponse{}
+	body := resp.Body.Bytes()
+	err := json.Unmarshal(body, &ur)
+	if err != nil {
+		t.Errorf("Failed to unmarshal response: %s", err)
+	}
+
+	expectedSettings := models.Settings{
+		StaticColorLabels:        []string{},
+		AnnotationsDefaultHidden: false,
+		AnnotationsHidden:        []string{},
+		AnnotationsVisible:       []string{},
+		Sorting: models.SortSettings{
+			Grid: models.GridSettings{
+				Order:   "startsAt",
+				Reverse: true,
+				Label:   "alertname",
+			},
+			ValueMapping: map[string]map[string]string{},
+		},
+		SilenceForm: models.SilenceFormSettings{
+			Strip: models.SilenceFormStripSettings{
+				Labels: []string{},
+			},
+			Author: "",
+		},
+		AlertAcknowledgement: models.AlertAcknowledgementSettings{
+			Enabled:         false,
+			DurationSeconds: 900,
+			Author:          "karma",
+			CommentPrefix:   "ACK!",
+		},
+	}
+
+	if diff := cmp.Diff(expectedSettings, ur.Settings); diff != "" {
+		t.Errorf("Wrong settings returned (-want +got):\n%s", diff)
+	}
+}
diff --git a/internal/config/config.go b/internal/config/config.go
index f3e9b48bc..c069fab1d 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -26,9 +26,13 @@ import (
 
 var (
 	// Config will hold final configuration read from the file and flags
-	Config configSchema
+	Config *configSchema
 )
 
+func init() {
+	Config = &configSchema{}
+}
+
 // SetupFlags is used to attach configuration flags to the main flag set
 func SetupFlags(f *pflag.FlagSet) {
 	f.Duration("alertmanager.interval", time.Minute,
@@ -225,6 +229,41 @@ func (config *configSchema) Read(flags *pflag.FlagSet) string {
 		log.Fatalf("Failed to unmarshal configuration: %v", err)
 	}
 
+	// FIXME workaround for https://github.com/mitchellh/mapstructure/issues/146
+	if config.Annotations.Hidden == nil {
+		config.Annotations.Hidden = []string{}
+	}
+	if config.Annotations.Visible == nil {
+		config.Annotations.Visible = []string{}
+	}
+	if config.Annotations.Keep == nil {
+		config.Annotations.Keep = []string{}
+	}
+	if config.Annotations.Strip == nil {
+		config.Annotations.Strip = []string{}
+	}
+	if config.Labels.Keep == nil {
+		config.Labels.Keep = []string{}
+	}
+	if config.Labels.Strip == nil {
+		config.Labels.Strip = []string{}
+	}
+	if config.Labels.Color.Static == nil {
+		config.Labels.Color.Static = []string{}
+	}
+	if config.Labels.Color.Unique == nil {
+		config.Labels.Color.Unique = []string{}
+	}
+	if config.Receivers.Keep == nil {
+		config.Receivers.Keep = []string{}
+	}
+	if config.Receivers.Strip == nil {
+		config.Receivers.Strip = []string{}
+	}
+	if config.SilenceForm.Strip.Labels == nil {
+		config.SilenceForm.Strip.Labels = []string{}
+	}
+
 	if config.SilenceForm.Author.PopulateFromHeader.ValueRegex != "" {
 		_, err = regexp.Compile(config.SilenceForm.Author.PopulateFromHeader.ValueRegex)
 		if err != nil {
@@ -284,7 +323,7 @@ func (config *configSchema) Read(flags *pflag.FlagSet) string {
 		}
 	}
 
-	Config = *config
+	Config = config
 
 	return configFileUsed
 }
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index b58aa8f8b..68691ea78 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -5,6 +5,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/prymitive/karma/internal/uri"
 	"github.com/spf13/pflag"
 
@@ -14,45 +15,8 @@ import (
 	yaml "gopkg.in/yaml.v2"
 )
 
-// unset all karma supported env variables before tests so we start with no
-// config from previous test run
 func resetEnv() {
-	karmaEnvVariables := []string{
-		"ALERTMANAGER_INTERVAL",
-		"ALERTMANAGER_URI",
-		"ALERTMANAGER_EXTERNAL_URI",
-		"ALERTMANAGER_NAME",
-		"ALERTMANAGET_TIMEOUT",
-		"ANNOTATIONS_DEFAULT_HIDDEN",
-		"ANNOTATIONS_HIDDEN",
-		"ANNOTATIONS_VISIBLE",
-		"CONFIG_FILE",
-		"CUSTOM_CSS",
-		"CUSTOM_JS",
-		"DEBUG",
-		"FILTERS_DEFAULT",
-		"KARMA_NAME",
-		"LABELS_COLOR_STATIC",
-		"LABELS_COLOR_UNIQUE",
-		"LABELS_KEEP",
-		"LABELS_STRIP",
-		"LISTEN_ADDRESS",
-		"LISTEN_PORT",
-		"LISTEN_PREFIX",
-		"LOG_CONFIG",
-		"LOG_LEVEL",
-		"RECEIVERS_KEEP",
-		"RECEIVERS_STRIP",
-		"SENTRY_PRIVATE",
-		"SENTRY_PUBLIC",
-
-		"HOST",
-		"PORT",
-		"SENTRY_DSN",
-	}
-	for _, env := range karmaEnvVariables {
-		os.Unsetenv(env)
-	}
+	os.Clearenv()
 }
 
 func testReadConfig(t *testing.T) {
@@ -349,3 +313,35 @@ func TestInvalidUITheme(t *testing.T) {
 		t.Error("Invalid ui.theme value didn't cause log.Fatal()")
 	}
 }
+
+func TestDefaultConfig(t *testing.T) {
+	resetEnv()
+	log.SetLevel(log.ErrorLevel)
+	mockConfigRead()
+
+	expectedConfig := configSchema{}
+	expectedConfig.Annotations.Hidden = []string{}
+	expectedConfig.Annotations.Visible = []string{}
+	expectedConfig.Annotations.Keep = []string{}
+	expectedConfig.Annotations.Strip = []string{}
+	expectedConfig.Labels.Keep = []string{}
+	expectedConfig.Labels.Strip = []string{}
+	expectedConfig.Labels.Color.Static = []string{}
+	expectedConfig.Labels.Color.Unique = []string{}
+	expectedConfig.Receivers.Keep = []string{}
+	expectedConfig.Receivers.Strip = []string{}
+	expectedConfig.SilenceForm.Strip.Labels = []string{}
+
+	if diff := cmp.Diff(expectedConfig.Annotations, Config.Annotations); diff != "" {
+		t.Errorf("Wrong annotations config returned (-want +got):\n%s", diff)
+	}
+	if diff := cmp.Diff(expectedConfig.Labels, Config.Labels); diff != "" {
+		t.Errorf("Wrong labels config returned (-want +got):\n%s", diff)
+	}
+	if diff := cmp.Diff(expectedConfig.Receivers, Config.Receivers); diff != "" {
+		t.Errorf("Wrong receivers config returned (-want +got):\n%s", diff)
+	}
+	if diff := cmp.Diff(expectedConfig.SilenceForm.Strip, Config.SilenceForm.Strip); diff != "" {
+		t.Errorf("Wrong silence form config returned (-want +got):\n%s", diff)
+	}
+}