diff --git a/errors.go b/errors.go
index 25e8ff60..9a317992 100644
--- a/errors.go
+++ b/errors.go
@@ -55,7 +55,7 @@ func (msg *Error) SetMeta(data interface{}) *Error {
 
 // JSON creates a properly formatted JSON
 func (msg *Error) JSON() interface{} {
-	json := H{}
+	jsonData := H{}
 	if msg.Meta != nil {
 		value := reflect.ValueOf(msg.Meta)
 		switch value.Kind() {
@@ -63,16 +63,16 @@ func (msg *Error) JSON() interface{} {
 			return msg.Meta
 		case reflect.Map:
 			for _, key := range value.MapKeys() {
-				json[key.String()] = value.MapIndex(key).Interface()
+				jsonData[key.String()] = value.MapIndex(key).Interface()
 			}
 		default:
-			json["meta"] = msg.Meta
+			jsonData["meta"] = msg.Meta
 		}
 	}
-	if _, ok := json["error"]; !ok {
-		json["error"] = msg.Error()
+	if _, ok := jsonData["error"]; !ok {
+		jsonData["error"] = msg.Error()
 	}
-	return json
+	return jsonData
 }
 
 // MarshalJSON implements the json.Marshaller interface.
@@ -135,17 +135,17 @@ func (a errorMsgs) Errors() []string {
 }
 
 func (a errorMsgs) JSON() interface{} {
-	switch len(a) {
+	switch length := len(a); length {
 	case 0:
 		return nil
 	case 1:
 		return a.Last().JSON()
 	default:
-		json := make([]interface{}, len(a))
+		jsonData := make([]interface{}, length)
 		for i, err := range a {
-			json[i] = err.JSON()
+			jsonData[i] = err.JSON()
 		}
-		return json
+		return jsonData
 	}
 }
 
diff --git a/fs.go b/fs.go
index 7a6738a6..007d9b75 100644
--- a/fs.go
+++ b/fs.go
@@ -9,7 +9,7 @@ import (
 	"os"
 )
 
-type onlyfilesFS struct {
+type onlyFilesFS struct {
 	fs http.FileSystem
 }
 
@@ -26,11 +26,11 @@ func Dir(root string, listDirectory bool) http.FileSystem {
 	if listDirectory {
 		return fs
 	}
-	return &onlyfilesFS{fs}
+	return &onlyFilesFS{fs}
 }
 
 // Open conforms to http.Filesystem.
-func (fs onlyfilesFS) Open(name string) (http.File, error) {
+func (fs onlyFilesFS) Open(name string) (http.File, error) {
 	f, err := fs.fs.Open(name)
 	if err != nil {
 		return nil, err
diff --git a/routergroup.go b/routergroup.go
index 9ff7c038..15d9930d 100644
--- a/routergroup.go
+++ b/routergroup.go
@@ -187,7 +187,7 @@ func (group *RouterGroup) createStaticHandler(relativePath string, fs http.FileS
 	fileServer := http.StripPrefix(absolutePath, http.FileServer(fs))
 
 	return func(c *Context) {
-		if _, nolisting := fs.(*onlyfilesFS); nolisting {
+		if _, noListing := fs.(*onlyFilesFS); noListing {
 			c.Writer.WriteHeader(http.StatusNotFound)
 		}