diff --git a/svc_key_test.go b/svc_key_test.go
index 4d0bc15..05ff35a 100644
--- a/svc_key_test.go
+++ b/svc_key_test.go
@@ -530,6 +530,115 @@ func TestKeyService_Create_AutomationsDisabled(t *testing.T) {
 	}
 }
 
+func TestKeyService_Create_PluralTranslationEncoded(t *testing.T) {
+	client, mux, _, teardown := setup()
+	defer teardown()
+
+	mux.HandleFunc(
+		fmt.Sprintf("/projects/%s/keys", testProjectID),
+		func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/json")
+			testMethod(t, r, "POST")
+			testHeader(t, r, apiTokenHeader, testApiToken)
+			data := `{
+			   "keys": [
+				  {
+					 "key_name": "index.welcome",
+					 "description": "Index app welcome",
+					 "platforms": [
+						"web"
+					 ],
+					 "translations": [
+						{
+						   "language_iso": "en",
+						   "translation": {
+							  "one": "oneText",
+							  "other": "otherText"
+						   }
+						}
+					 ],
+					 "is_plural": true
+				  }
+			   ]
+			}`
+
+			req := new(bytes.Buffer)
+			_ = json.Compact(req, []byte(data))
+
+			testBody(t, r, req.String())
+
+			_, _ = fmt.Fprint(w, `{
+				"project_id": "3002780358964f9bab5a92.87762498",
+				"keys": [
+					{
+						"key_id": 331223,
+						"created_at": "2018-12-31 12:00:00 (Etc/UTC)",
+						"created_at_timestamp": 1546257600,
+						"key_name": {
+							"ios": "index.welcome",
+							"android": "index.welcome",
+							"web": "index.welcome",
+							"other": "index.welcome"
+						},
+						"filenames": {
+							"ios": "",
+							"android": "",
+							"web": "",
+							"other": ""
+						},
+						"description": "Index app welcome",
+						"platforms": [
+							"web"
+						],
+						"tags": [],
+						"comments": [],
+						"screenshots": [],
+						"translations": [
+							{
+								"translation_id": 444921,
+								"key_id": 331223,
+								"language_iso": "en",
+								"translation": "Welcome",
+								"modified_by": 420,
+								"modified_by_email": "user@mycompany.com",
+								"modified_at": "2018-12-31 12:00:00 (Etc/UTC)",
+								"modified_at_timestamp": 1546257600,
+								"is_reviewed": false,
+								"reviewed_by": 0,
+								"words": 0
+							}
+						]
+					}
+				],
+				"errors": [
+					{
+						"message": "This key name is already taken",
+						"code": 400,
+						"key": {
+							"key_name": "index.hello"
+						}
+					}
+				]
+			}`)
+		})
+
+	_, _ = client.Keys().Create(testProjectID, []NewKey{
+		{
+			KeyName:     "index.welcome",
+			Description: "Index app welcome",
+			Platforms:   []string{"web"},
+			IsPlural:    true,
+			Translations: []NewTranslation{
+				{
+					LanguageISO: "en",
+					Translation: "{\"one\":\"oneText\",\"other\":\"otherText\"}",
+				},
+			},
+		},
+	})
+
+}
+
 func TestKeyService_Delete(t *testing.T) {
 	client, mux, _, teardown := setup()
 	defer teardown()
diff --git a/svc_translation.go b/svc_translation.go
index a987255..f031312 100644
--- a/svc_translation.go
+++ b/svc_translation.go
@@ -1,8 +1,8 @@
 package lokalise
 
 import (
+	"encoding/json"
 	"fmt"
-
 	"github.com/go-resty/resty/v2"
 	"github.com/google/go-querystring/query"
 )
@@ -53,6 +53,62 @@ type NewTranslation struct {
 	MergeCustomTranslationStatuses bool    `json:"merge_custom_translation_statuses,omitempty"`
 }
 
+func (t NewTranslation) MarshalJSON() ([]byte, error) {
+	type Alias NewTranslation
+
+	var translation interface{} = t.Translation
+
+	if json.Valid([]byte(t.Translation)) {
+		_ = json.Unmarshal([]byte(t.Translation), &translation)
+	}
+
+	return json.Marshal(&struct {
+		LanguageISO string      `json:"language_iso"`
+		Translation interface{} `json:"translation"`
+		Alias
+	}{
+		LanguageISO: t.LanguageISO,
+		Translation: translation,
+		Alias:       (Alias)(t),
+	})
+}
+
+func (t *NewTranslation) UnmarshalJSON(data []byte) error {
+	type Alias NewTranslation
+	aux := &struct {
+		LanguageISO string      `json:"language_iso"`
+		Translation interface{} `json:"translation"`
+		*Alias
+	}{
+		Alias: (*Alias)(t),
+	}
+
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+
+	switch aux.Translation.(type) {
+	case map[string]interface{}:
+		marshal, err := json.Marshal(aux.Translation)
+		if err != nil {
+			return err
+		}
+		t.Translation = string(marshal)
+	case string:
+		t.Translation = fmt.Sprintf("%+v", aux.Translation)
+	default:
+		return fmt.Errorf("NewTranslation tranlation type is of unknown type")
+	}
+
+	t.LanguageISO = aux.LanguageISO
+	t.IsFuzzy = aux.IsFuzzy
+	t.IsReviewed = aux.IsReviewed
+	t.CustomTranslationStatusIds = aux.CustomTranslationStatusIds
+	t.MergeCustomTranslationStatuses = aux.MergeCustomTranslationStatuses
+
+	return nil
+}
+
 type UpdateTranslation struct {
 	Translation                string   `json:"translation"`
 	IsFuzzy                    *bool    `json:"is_fuzzy,omitempty"`
@@ -60,6 +116,58 @@ type UpdateTranslation struct {
 	CustomTranslationStatusIDs []string `json:"custom_translation_status_ids,omitempty"`
 }
 
+func (t UpdateTranslation) MarshalJSON() ([]byte, error) {
+	type Alias UpdateTranslation
+
+	var translation interface{} = t.Translation
+
+	if json.Valid([]byte(t.Translation)) {
+		_ = json.Unmarshal([]byte(t.Translation), &translation)
+	}
+
+	return json.Marshal(&struct {
+		Translation interface{} `json:"translation"`
+		Alias
+	}{
+		Translation: translation,
+		Alias:       (Alias)(t),
+	})
+}
+
+func (t *UpdateTranslation) UnmarshalJSON(data []byte) error {
+	type Alias UpdateTranslation
+	aux := &struct {
+		LanguageISO string      `json:"language_iso"`
+		Translation interface{} `json:"translation"`
+		*Alias
+	}{
+		Alias: (*Alias)(t),
+	}
+
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+
+	switch aux.Translation.(type) {
+	case map[string]interface{}:
+		marshal, err := json.Marshal(aux.Translation)
+		if err != nil {
+			return err
+		}
+		t.Translation = string(marshal)
+	case string:
+		t.Translation = fmt.Sprintf("%+v", aux.Translation)
+	default:
+		return fmt.Errorf("NewTranslation tranlation type is of unknown type")
+	}
+
+	t.IsFuzzy = aux.IsFuzzy
+	t.IsReviewed = aux.IsReviewed
+	t.CustomTranslationStatusIDs = aux.CustomTranslationStatusIDs
+
+	return nil
+}
+
 type TranslationsResponse struct {
 	Paged
 	Translations []Translation `json:"translations"`
diff --git a/svc_translation_test.go b/svc_translation_test.go
index c55031c..362e2e8 100644
--- a/svc_translation_test.go
+++ b/svc_translation_test.go
@@ -210,3 +210,156 @@ func TestTranslationService_Update(t *testing.T) {
 		t.Errorf("Translations.Update returned %+v, want %+v", r.Translation, want)
 	}
 }
+
+func TestNewTranslation_MarshalJSON(t *testing.T) {
+	translations := []NewTranslation{
+		{
+			LanguageISO: "en",
+			Translation: "simple text",
+		},
+		{
+			LanguageISO: "en",
+			Translation: "{\"one\":\"oneText\",\"other\":\"otherText\"}",
+		},
+	}
+
+	want := JsonCompact(`
+	[
+		{
+		   "language_iso": "en",
+		   "translation": "simple text"
+		},
+		{
+		   "language_iso": "en",
+		   "translation": {
+			  "one": "oneText",
+			  "other": "otherText"
+		   }
+		}
+ 	]`)
+
+	marshal, err := json.Marshal(translations)
+	if err != nil {
+		t.Errorf("NewTranslation marshalling returned error %s", err)
+	}
+
+	if string(marshal) != want {
+		t.Errorf("NewTranslation marshalling mismatch: %+v, want %+v", string(marshal), want)
+	}
+}
+
+func TestUpdateTranslation_MarshalJSON(t *testing.T) {
+	translations := []UpdateTranslation{
+		{
+			Translation: "simple text",
+		},
+		{
+			Translation: "{\"one\":\"oneText\",\"other\":\"otherText\"}",
+		},
+	}
+
+	want := JsonCompact(`
+	[
+		{
+		   "translation": "simple text"
+		},
+		{
+		   "translation": {
+			  "one": "oneText",
+			  "other": "otherText"
+		   }
+		}
+ 	]`)
+
+	marshal, err := json.Marshal(translations)
+	if err != nil {
+		t.Errorf("UpdateTranslation marshalling returned error %s", err)
+	}
+
+	if string(marshal) != want {
+		t.Errorf("UpdateTranslation marshalling mismatch: %+v, want %+v", string(marshal), want)
+	}
+}
+
+func TestNewTranslation_UnmarshalJSON(t *testing.T) {
+	raw := `
+	[
+		{
+		   "language_iso": "en",
+		   "translation": "simple text"
+		},
+		{
+		   "language_iso": "en",
+		   "translation": {
+			  "one": "oneText",
+			  "other": "otherText"
+		   }
+		}
+ 	]`
+
+	want := []NewTranslation{
+		{
+			LanguageISO: "en",
+			Translation: "simple text",
+		},
+		{
+			LanguageISO: "en",
+			Translation: "{\"one\":\"oneText\",\"other\":\"otherText\"}",
+		},
+	}
+
+	var result []NewTranslation
+
+	err := json.Unmarshal([]byte(raw), &result)
+	if err != nil {
+		t.Errorf("NewTranslation unmarshalling returned error %s", err)
+	}
+
+	if !reflect.DeepEqual(want, result) {
+		t.Errorf("NewTranslation unmarshalling mismatch: %+v, want %+v", result, want)
+	}
+}
+
+func TestUpdateTranslation_UnmarshalJSON(t *testing.T) {
+	raw := `
+	[
+		{
+		   "translation": "simple text"
+		},
+		{
+		   "translation": {
+			  "one": "oneText",
+			  "other": "otherText"
+		   }
+		}
+ 	]`
+
+	want := []UpdateTranslation{
+		{
+			Translation: "simple text",
+		},
+		{
+			Translation: "{\"one\":\"oneText\",\"other\":\"otherText\"}",
+		},
+	}
+
+	var result []UpdateTranslation
+
+	err := json.Unmarshal([]byte(raw), &result)
+	if err != nil {
+		t.Errorf("UpdateTranslation unmarshalling returned error %s", err)
+	}
+
+	if !reflect.DeepEqual(want, result) {
+		t.Errorf("UpdateTranslation unmarshalling mismatch: %+v, want %+v", result, want)
+	}
+}
+
+func JsonCompact(text string) string {
+	compactedBuffer := new(bytes.Buffer)
+	err := json.Compact(compactedBuffer, []byte(text))
+	if err != nil {
+		panic(fmt.Sprintf("Invalid test data definition %+v", err))
+	}
+	return compactedBuffer.String()
+}