diff --git a/config/config.go b/config/config.go
index ab4f5fe..78626cb 100644
--- a/config/config.go
+++ b/config/config.go
@@ -22,9 +22,9 @@ type Config struct {
 			AllowSkewness TypeDuration `json:"allow-skewness"`
 		} `json:"time"`
 		AntiReplay struct {
-			Enabled   bool      `json:"enabled"`
-			MaxSize   TypeBytes `json:"max-size"`
-			ErrorRate TypeFloat `json:"error-rate"`
+			Enabled   bool          `json:"enabled"`
+			MaxSize   TypeBytes     `json:"max-size"`
+			ErrorRate TypeErrorRate `json:"error-rate"`
 		} `json:"anti-replay"`
 	} `json:"probes"`
 	Network struct {
diff --git a/config/type_float.go b/config/type_error_rate.go
similarity index 50%
rename from config/type_float.go
rename to config/type_error_rate.go
index f30ccb4..690d85e 100644
--- a/config/type_float.go
+++ b/config/type_error_rate.go
@@ -5,18 +5,18 @@ import (
 	"strconv"
 )
 
-type TypeFloat struct {
+type TypeErrorRate struct {
 	value float64
 }
 
-func (c *TypeFloat) UnmarshalJSON(data []byte) error {
+func (c *TypeErrorRate) UnmarshalJSON(data []byte) error {
 	value, err := strconv.ParseFloat(string(data), 64)
 	if err != nil {
 		return fmt.Errorf("incorrect float value: %w", err)
 	}
 
-	if value < 0 {
-		return fmt.Errorf("%f should be positive", value)
+	if value <= 0 || value >= 100 {
+		return fmt.Errorf("%f should be 0 < x < 100", value)
 	}
 
 	c.value = value
@@ -24,16 +24,16 @@ func (c *TypeFloat) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
-func (c *TypeFloat) MarshalText() ([]byte, error) {
+func (c *TypeErrorRate) MarshalText() ([]byte, error) {
 	return []byte(c.String()), nil
 }
 
-func (c TypeFloat) String() string {
+func (c TypeErrorRate) String() string {
 	return strconv.FormatFloat(c.value, 'f', -1, 64)
 }
 
-func (c TypeFloat) Value(defaultValue float64) float64 {
-	if c.value < 0.00001 {
+func (c TypeErrorRate) Value(defaultValue float64) float64 {
+	if c.value < 1e-8 {
 		return defaultValue
 	}
 
diff --git a/config/type_error_rate_test.go b/config/type_error_rate_test.go
new file mode 100644
index 0000000..971b787
--- /dev/null
+++ b/config/type_error_rate_test.go
@@ -0,0 +1,119 @@
+package config_test
+
+import (
+	"encoding/json"
+	"strconv"
+	"testing"
+
+	"github.com/9seconds/mtg/v2/config"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+)
+
+type typeErrorRateTestStruct struct {
+	Value config.TypeErrorRate `json:"value"`
+}
+
+type TypeErrorRateTestSuite struct {
+	suite.Suite
+}
+
+func (suite *TypeErrorRateTestSuite) TestUnmarshalFail() {
+	testData := []float64{
+		1000,
+		-100,
+		-0.0001,
+	}
+
+	for _, v := range testData {
+		data, err := json.Marshal(map[string]float64{
+			"value": v,
+		})
+		suite.NoError(err)
+
+		suite.T().Run(strconv.FormatFloat(v, 'f', -1, 64), func(t *testing.T) {
+			assert.Error(t, json.Unmarshal(data, &typeErrorRateTestStruct{}))
+		})
+	}
+}
+
+func (suite *TypeErrorRateTestSuite) TestUnmarshalOk() {
+	testData := []float64{
+		1,
+		55.5,
+		0.0001,
+		1e-6,
+	}
+
+	for _, v := range testData {
+		value := v
+
+		data, err := json.Marshal(map[string]float64{
+			"value": v,
+		})
+		suite.NoError(err)
+
+		suite.T().Run(strconv.FormatFloat(v, 'f', -1, 64), func(t *testing.T) {
+			testStruct := &typeErrorRateTestStruct{}
+
+			assert.NoError(t, json.Unmarshal(data, testStruct))
+			assert.InEpsilon(t, value, testStruct.Value.Value(0), 1e-10)
+		})
+	}
+}
+
+func (suite *TypeErrorRateTestSuite) TestMarshalOk() {
+	testData := []float64{
+		1,
+		55.5,
+		0.0001,
+		1e-6,
+	}
+
+	for _, v := range testData {
+		value := v
+
+		data, err := json.Marshal(map[string]float64{
+			"value": v,
+		})
+		suite.NoError(err)
+
+		suite.T().Run(strconv.FormatFloat(v, 'f', -1, 64), func(t *testing.T) {
+			testStruct := &typeErrorRateTestStruct{}
+
+			assert.NoError(t, json.Unmarshal(data, testStruct))
+
+			parsed, err := strconv.ParseFloat(testStruct.Value.String(), 64)
+			assert.NoError(t, err)
+			assert.InEpsilon(t, value, parsed, 1e-10)
+
+			marshalled, err := testStruct.Value.MarshalText()
+			assert.NoError(t, err)
+
+			parsed, err = strconv.ParseFloat(string(marshalled), 64)
+			assert.NoError(t, err)
+			assert.InEpsilon(t, value, parsed, 1e-10)
+		})
+	}
+}
+
+func (suite *TypeErrorRateTestSuite) TestValue() {
+	testStruct := &typeErrorRateTestStruct{}
+
+	suite.InEpsilon(1, testStruct.Value.Value(1), 1e-10)
+	suite.InEpsilon(2, testStruct.Value.Value(2), 1e-10)
+
+	data, err := json.Marshal(map[string]float64{
+		"value": 1,
+	})
+	suite.NoError(err)
+	suite.NoError(json.Unmarshal(data, testStruct))
+
+	suite.InEpsilon(1, testStruct.Value.Value(2), 1e-10)
+	suite.InEpsilon(1, testStruct.Value.Value(3), 1e-10)
+}
+
+func TestTypeErrorRate(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &TypeErrorRateTestSuite{})
+}