diff --git a/internal/config/config.go b/internal/config/config.go
index 5c524e1525..5740cd5f1d 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -7,31 +7,21 @@ import (
 	"path/filepath"
 
 	"github.com/BurntSushi/toml"
-	"github.com/ghodss/yaml"
+	"gopkg.in/yaml.v2"
 
 	"github.com/caos/zitadel/internal/errors"
 )
 
-type Reader interface {
-	Unmarshal(data []byte, o interface{}) error
-}
-
 type ValidatableConfiguration interface {
 	Validate() error
 }
 
 type ReaderFunc func(data []byte, o interface{}) error
 
-func (c ReaderFunc) Unmarshal(data []byte, o interface{}) error {
-	return c(data, o)
-}
-
 var (
-	JSONReader = ReaderFunc(json.Unmarshal)
-	TOMLReader = ReaderFunc(toml.Unmarshal)
-	YAMLReader = ReaderFunc(func(y []byte, o interface{}) error {
-		return yaml.Unmarshal(y, o)
-	})
+	JSONReader = json.Unmarshal
+	TOMLReader = toml.Unmarshal
+	YAMLReader = yaml.Unmarshal
 )
 
 // Read deserializes each config file to the target obj
@@ -39,11 +29,11 @@ var (
 // env vars are replaced in the config file as well as the file path
 func Read(obj interface{}, configFiles ...string) error {
 	for _, cf := range configFiles {
-		configReader, err := configReaderForFile(cf)
+		readerFunc, err := readerFuncForFile(cf)
 		if err != nil {
 			return err
 		}
-		if err := readConfigFile(configReader, cf, obj); err != nil {
+		if err := readConfigFile(readerFunc, cf, obj); err != nil {
 			return err
 		}
 	}
@@ -57,13 +47,9 @@ func Read(obj interface{}, configFiles ...string) error {
 	return nil
 }
 
-func readConfigFile(configReader Reader, configFile string, obj interface{}) error {
+func readConfigFile(readerFunc ReaderFunc, configFile string, obj interface{}) error {
 	configFile = os.ExpandEnv(configFile)
 
-	if _, err := os.Stat(configFile); err != nil {
-		return errors.ThrowNotFoundf(err, "CONFI-Hs93M", "config file %s does not exist", configFile)
-	}
-
 	configStr, err := ioutil.ReadFile(configFile)
 	if err != nil {
 		return errors.ThrowInternalf(err, "CONFI-nJk2a", "failed to read config file %s", configFile)
@@ -71,14 +57,14 @@ func readConfigFile(configReader Reader, configFile string, obj interface{}) err
 
 	configStr = []byte(os.ExpandEnv(string(configStr)))
 
-	if err := configReader.Unmarshal(configStr, obj); err != nil {
+	if err := readerFunc(configStr, obj); err != nil {
 		return errors.ThrowInternalf(err, "CONFI-2Mc3c", "error parse config file %s", configFile)
 	}
 
 	return nil
 }
 
-func configReaderForFile(configFile string) (Reader, error) {
+func readerFuncForFile(configFile string) (ReaderFunc, error) {
 	ext := filepath.Ext(configFile)
 	switch ext {
 	case ".yaml", ".yml":
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
new file mode 100644
index 0000000000..ba517b6061
--- /dev/null
+++ b/internal/config/config_test.go
@@ -0,0 +1,198 @@
+package config
+
+import (
+	"errors"
+	"reflect"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type test struct {
+	Test bool
+}
+
+type validatable struct {
+	Test bool
+}
+
+func (v *validatable) Validate() error {
+	if v.Test {
+		return nil
+	}
+	return errors.New("invalid")
+}
+
+func TestRead(t *testing.T) {
+	type args struct {
+		obj         interface{}
+		configFiles []string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr bool
+	}{
+		{
+			"not supoorted config file error",
+			args{
+				configFiles: []string{"notsupported.unknown"},
+				obj:         nil,
+			},
+			true,
+		},
+		{
+			"non existing config file error",
+			args{
+				configFiles: []string{"nonexisting.yaml"},
+				obj:         nil,
+			},
+			true,
+		},
+		{
+			"non parsable config file error",
+			args{
+				configFiles: []string{"./testdata/non_parsable.json"},
+				obj:         &test{},
+			},
+			true,
+		},
+		{
+			"invalid parsable config file error",
+			args{
+				configFiles: []string{"./testdata/invalid.json"},
+				obj:         &validatable{},
+			},
+			true,
+		},
+		{
+			"parsable config file ok",
+			args{
+				configFiles: []string{"./testdata/valid.json"},
+				obj:         &test{},
+			},
+			false,
+		},
+		{
+			"valid parsable config file ok",
+			args{
+				configFiles: []string{"./testdata/valid.json"},
+				obj:         &validatable{},
+			},
+			false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := Read(tt.args.obj, tt.args.configFiles...); (err != nil) != tt.wantErr {
+				t.Errorf("Read() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func Test_readerFuncForFile(t *testing.T) {
+	type args struct {
+		configFile string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    ReaderFunc
+		wantErr bool
+	}{
+		{
+			"unknown extension error",
+			args{configFile: "test.unknown"},
+			nil,
+			true,
+		},
+		{
+			"toml",
+			args{configFile: "test.toml"},
+			TOMLReader,
+			false,
+		},
+		{
+			"json",
+			args{configFile: "test.json"},
+			JSONReader,
+			false,
+		},
+		{
+			"yaml",
+			args{configFile: "test.yaml"},
+			YAMLReader,
+			false,
+		},
+		{
+			"yml",
+			args{configFile: "test.yml"},
+			YAMLReader,
+			false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := readerFuncForFile(tt.args.configFile)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("configReaderForFile() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			funcName1 := runtime.FuncForPC(reflect.ValueOf(got).Pointer()).Name()
+			funcName2 := runtime.FuncForPC(reflect.ValueOf(tt.want).Pointer()).Name()
+			if !assert.Equal(t, funcName1, funcName2) {
+				t.Errorf("configReaderForFile() got = %v, want %v", funcName1, funcName2)
+			}
+		})
+	}
+}
+
+func Test_readConfigFile(t *testing.T) {
+	type args struct {
+		configReader ReaderFunc
+		configFile   string
+		obj          interface{}
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr bool
+	}{
+		{
+			"non existing config file error",
+			args{
+				configReader: YAMLReader,
+				configFile:   "nonexisting.json",
+				obj:          nil,
+			},
+			true,
+		},
+		{
+			"non parsable config file error",
+			args{
+				configReader: YAMLReader,
+				configFile:   "./testdata/non_parsable.json",
+				obj:          &test{},
+			},
+			true,
+		},
+		{
+			"parsable config file no error",
+			args{
+				configReader: YAMLReader,
+				configFile:   "./testdata/valid.json",
+				obj:          &test{},
+			},
+			false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := readConfigFile(tt.args.configReader, tt.args.configFile, tt.args.obj); (err != nil) != tt.wantErr {
+				t.Errorf("readConfigFile() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
diff --git a/internal/config/testdata/invalid.json b/internal/config/testdata/invalid.json
new file mode 100644
index 0000000000..454b39367e
--- /dev/null
+++ b/internal/config/testdata/invalid.json
@@ -0,0 +1,3 @@
+{
+  "Test" : false
+}
\ No newline at end of file
diff --git a/internal/config/testdata/non_parsable.json b/internal/config/testdata/non_parsable.json
new file mode 100644
index 0000000000..8318c86b35
--- /dev/null
+++ b/internal/config/testdata/non_parsable.json
@@ -0,0 +1 @@
+Test
\ No newline at end of file
diff --git a/internal/config/testdata/valid.json b/internal/config/testdata/valid.json
new file mode 100644
index 0000000000..65f3700045
--- /dev/null
+++ b/internal/config/testdata/valid.json
@@ -0,0 +1,3 @@
+{
+  "Test" : true
+}
\ No newline at end of file