diff --git a/render/data.go b/render/data.go
index efa75d55..c296042c 100644
--- a/render/data.go
+++ b/render/data.go
@@ -11,10 +11,13 @@ type Data struct {
 	Data        []byte
 }
 
-func (r Data) Render(w http.ResponseWriter) error {
-	if len(r.ContentType) > 0 {
-		w.Header()["Content-Type"] = []string{r.ContentType}
-	}
-	w.Write(r.Data)
-	return nil
+// Render (Data) writes data with custom ContentType
+func (r Data) Render(w http.ResponseWriter) (err error) {
+	r.WriteContentType(w)
+	_, err = w.Write(r.Data)
+	return
+}
+
+func (r Data) WriteContentType(w http.ResponseWriter) {
+	writeContentType(w, []string{r.ContentType})
 }
diff --git a/render/html.go b/render/html.go
index 8bfb23ac..a3cbda67 100644
--- a/render/html.go
+++ b/render/html.go
@@ -58,9 +58,14 @@ func (r HTMLDebug) loadTemplate() *template.Template {
 }
 
 func (r HTML) Render(w http.ResponseWriter) error {
-	writeContentType(w, htmlContentType)
+	r.WriteContentType(w)
+
 	if len(r.Name) == 0 {
 		return r.Template.Execute(w, r.Data)
 	}
 	return r.Template.ExecuteTemplate(w, r.Name, r.Data)
 }
+
+func (r HTML) WriteContentType(w http.ResponseWriter) {
+	writeContentType(w, htmlContentType)
+}
diff --git a/render/json.go b/render/json.go
index b652c4c8..0c87399d 100644
--- a/render/json.go
+++ b/render/json.go
@@ -21,12 +21,24 @@ type (
 
 var jsonContentType = []string{"application/json; charset=utf-8"}
 
-func (r JSON) Render(w http.ResponseWriter) error {
-	return WriteJSON(w, r.Data)
+func (r JSON) Render(w http.ResponseWriter) (err error) {
+	if err = WriteJSON(w, r.Data); err != nil {
+		panic(err)
+	}
+	return
+}
+
+func (r JSON) WriteContentType(w http.ResponseWriter) {
+	writeContentType(w, jsonContentType)
+}
+
+func WriteJSON(w http.ResponseWriter, obj interface{}) error {
+	writeContentType(w, jsonContentType)
+	return json.NewEncoder(w).Encode(obj)
 }
 
 func (r IndentedJSON) Render(w http.ResponseWriter) error {
-	writeContentType(w, jsonContentType)
+	r.WriteContentType(w)
 	jsonBytes, err := json.MarshalIndent(r.Data, "", "    ")
 	if err != nil {
 		return err
@@ -35,12 +47,6 @@ func (r IndentedJSON) Render(w http.ResponseWriter) error {
 	return nil
 }
 
-func WriteJSON(w http.ResponseWriter, obj interface{}) error {
+func (r IndentedJSON) WriteContentType(w http.ResponseWriter) {
 	writeContentType(w, jsonContentType)
-	jsonBytes, err := json.Marshal(obj)
-	if err != nil {
-		return err
-	}
-	w.Write(jsonBytes)
-	return nil
 }
diff --git a/render/redirect.go b/render/redirect.go
index bd48d7d8..f874a351 100644
--- a/render/redirect.go
+++ b/render/redirect.go
@@ -22,3 +22,5 @@ func (r Redirect) Render(w http.ResponseWriter) error {
 	http.Redirect(w, r.Request, r.Location, r.Code)
 	return nil
 }
+
+func (r Redirect) WriteContentType(http.ResponseWriter) {}
diff --git a/render/render.go b/render/render.go
index 3808666a..7e997374 100644
--- a/render/render.go
+++ b/render/render.go
@@ -8,6 +8,7 @@ import "net/http"
 
 type Render interface {
 	Render(http.ResponseWriter) error
+	WriteContentType(w http.ResponseWriter)
 }
 
 var (
diff --git a/render/text.go b/render/text.go
index 5a9e280b..74cd26be 100644
--- a/render/text.go
+++ b/render/text.go
@@ -22,9 +22,12 @@ func (r String) Render(w http.ResponseWriter) error {
 	return nil
 }
 
+func (r String) WriteContentType(w http.ResponseWriter) {
+	writeContentType(w, plainContentType)
+}
+
 func WriteString(w http.ResponseWriter, format string, data []interface{}) {
 	writeContentType(w, plainContentType)
-
 	if len(data) > 0 {
 		fmt.Fprintf(w, format, data...)
 	} else {
diff --git a/render/xml.go b/render/xml.go
index be22e6f2..cff1ac3e 100644
--- a/render/xml.go
+++ b/render/xml.go
@@ -16,6 +16,10 @@ type XML struct {
 var xmlContentType = []string{"application/xml; charset=utf-8"}
 
 func (r XML) Render(w http.ResponseWriter) error {
-	writeContentType(w, xmlContentType)
+	r.WriteContentType(w)
 	return xml.NewEncoder(w).Encode(r.Data)
 }
+
+func (r XML) WriteContentType(w http.ResponseWriter) {
+	writeContentType(w, xmlContentType)
+}
diff --git a/render/yaml.go b/render/yaml.go
index 46937d88..25d0ebd4 100644
--- a/render/yaml.go
+++ b/render/yaml.go
@@ -17,7 +17,7 @@ type YAML struct {
 var yamlContentType = []string{"application/x-yaml; charset=utf-8"}
 
 func (r YAML) Render(w http.ResponseWriter) error {
-	writeContentType(w, yamlContentType)
+	r.WriteContentType(w)
 
 	bytes, err := yaml.Marshal(r.Data)
 	if err != nil {
@@ -27,3 +27,7 @@ func (r YAML) Render(w http.ResponseWriter) error {
 	w.Write(bytes)
 	return nil
 }
+
+func (r YAML) WriteContentType(w http.ResponseWriter) {
+	writeContentType(w, yamlContentType)
+}