diff --git a/sentry/metric_alerts_test.go b/sentry/metric_alerts_test.go
index 221aabb..8412700 100644
--- a/sentry/metric_alerts_test.go
+++ b/sentry/metric_alerts_test.go
@@ -95,7 +95,7 @@ func TestMetricAlertService_List(t *testing.T) {
 							AlertRuleTriggerID: String("12345"),
 							Type:               String("slack"),
 							TargetType:         String("specific"),
-							TargetIdentifier:   &Int64OrString{IsString: true, String: "#alert-rule-alerts"},
+							TargetIdentifier:   &Int64OrString{IsString: true, StringVal: "#alert-rule-alerts"},
 							InputChannelID:     String("C038NF00X4F"),
 							IntegrationID:      Int(123),
 							DateCreated:        Time(mustParseTime("2022-04-07T16:46:49.154638Z")),
@@ -195,7 +195,7 @@ func TestMetricAlertService_Get(t *testing.T) {
 						AlertRuleTriggerID: String("56789"),
 						Type:               String("slack"),
 						TargetType:         String("specific"),
-						TargetIdentifier:   &Int64OrString{IsString: true, String: "#alert-rule-alerts"},
+						TargetIdentifier:   &Int64OrString{IsString: true, StringVal: "#alert-rule-alerts"},
 						InputChannelID:     String("C0XXXFKLXXX"),
 						IntegrationID:      Int(111),
 						DateCreated:        Time(mustParseTime("2022-04-15T15:06:01.087054Z")),
@@ -339,7 +339,7 @@ func TestMetricAlertsService_CreateWithAsyncTask(t *testing.T) {
 						AlertRuleTriggerID: String("56789"),
 						Type:               String("slack"),
 						TargetType:         String("specific"),
-						TargetIdentifier:   &Int64OrString{IsString: true, String: "#alert-rule-alerts"},
+						TargetIdentifier:   &Int64OrString{IsString: true, StringVal: "#alert-rule-alerts"},
 						InputChannelID:     String("C0XXXFKLXXX"),
 						IntegrationID:      Int(123),
 						DateCreated:        Time(mustParseTime("2022-04-15T15:06:01.087054Z")),
@@ -381,7 +381,7 @@ func TestMetricAlertsService_CreateWithAsyncTask(t *testing.T) {
 						AlertRuleTriggerID: String("56789"),
 						Type:               String("slack"),
 						TargetType:         String("specific"),
-						TargetIdentifier:   &Int64OrString{IsString: true, String: "#alert-rule-alerts"},
+						TargetIdentifier:   &Int64OrString{IsString: true, StringVal: "#alert-rule-alerts"},
 						InputChannelID:     String("C0XXXFKLXXX"),
 						IntegrationID:      Int(111),
 						DateCreated:        Time(mustParseTime("2022-04-15T15:06:01.087054Z")),
@@ -475,7 +475,7 @@ func TestMetricAlertService_Create(t *testing.T) {
 						AlertRuleTriggerID: String("56789"),
 						Type:               String("slack"),
 						TargetType:         String("specific"),
-						TargetIdentifier:   &Int64OrString{IsString: true, String: "#alert-rule-alerts"},
+						TargetIdentifier:   &Int64OrString{IsString: true, StringVal: "#alert-rule-alerts"},
 						InputChannelID:     String("C0XXXFKLXXX"),
 						IntegrationID:      Int(123),
 						DateCreated:        Time(mustParseTime("2022-04-15T15:06:01.087054Z")),
@@ -517,7 +517,7 @@ func TestMetricAlertService_Create(t *testing.T) {
 						AlertRuleTriggerID: String("56789"),
 						Type:               String("slack"),
 						TargetType:         String("specific"),
-						TargetIdentifier:   &Int64OrString{IsString: true, String: "#alert-rule-alerts"},
+						TargetIdentifier:   &Int64OrString{IsString: true, StringVal: "#alert-rule-alerts"},
 						InputChannelID:     String("C0XXXFKLXXX"),
 						IntegrationID:      Int(111),
 						DateCreated:        Time(mustParseTime("2022-04-15T15:06:01.087054Z")),
@@ -668,7 +668,7 @@ func TestMetricAlertService_Update(t *testing.T) {
 						AlertRuleTriggerID: String("56789"),
 						Type:               String("slack"),
 						TargetType:         String("specific"),
-						TargetIdentifier:   &Int64OrString{IsString: true, String: "#alert-rule-alerts"},
+						TargetIdentifier:   &Int64OrString{IsString: true, StringVal: "#alert-rule-alerts"},
 						InputChannelID:     String("C0XXXFKLXXX"),
 						IntegrationID:      Int(111),
 						DateCreated:        Time(mustParseTime("2022-04-15T15:06:01.087054Z")),
diff --git a/sentry/types.go b/sentry/types.go
index ebc6c4f..937caab 100644
--- a/sentry/types.go
+++ b/sentry/types.go
@@ -15,6 +15,7 @@ type BoolOrStringSlice struct {
 }
 
 var _ json.Unmarshaler = (*BoolOrStringSlice)(nil)
+var _ json.Marshaler = (*BoolOrStringSlice)(nil)
 
 // UnmarshalJSON implements json.Unmarshaler.
 func (bos *BoolOrStringSlice) UnmarshalJSON(data []byte) error {
@@ -40,16 +41,24 @@ func (bos *BoolOrStringSlice) UnmarshalJSON(data []byte) error {
 	return fmt.Errorf("unable to unmarshal as bool or string slice: %s", string(data))
 }
 
+func (bos BoolOrStringSlice) MarshalJSON() ([]byte, error) {
+	if bos.IsBool {
+		return json.Marshal(bos.BoolVal)
+	}
+	return json.Marshal(bos.StringSliceVal)
+}
+
 // Int64OrString is a type that can be unmarshaled from either an int64 or a
 // string.
 type Int64OrString struct {
-	IsInt64  bool
-	IsString bool
-	Int64Val int64
-	String   string
+	IsInt64   bool
+	IsString  bool
+	Int64Val  int64
+	StringVal string
 }
 
 var _ json.Unmarshaler = (*Int64OrString)(nil)
+var _ json.Marshaler = (*Int64OrString)(nil)
 
 func (ios *Int64OrString) UnmarshalJSON(data []byte) error {
 	// Try to unmarshal as an int64
@@ -66,10 +75,17 @@ func (ios *Int64OrString) UnmarshalJSON(data []byte) error {
 	if err := json.Unmarshal(data, &stringVal); err == nil {
 		ios.IsInt64 = false
 		ios.IsString = true
-		ios.String = stringVal
+		ios.StringVal = stringVal
 		return nil
 	}
 
 	// If neither worked, return an error
 	return fmt.Errorf("unable to unmarshal as int64 or string: %s", string(data))
 }
+
+func (ios Int64OrString) MarshalJSON() ([]byte, error) {
+	if ios.IsInt64 {
+		return json.Marshal(ios.Int64Val)
+	}
+	return json.Marshal(ios.StringVal)
+}