diff --git a/server.go b/server.go
index 0b644d1..838af13 100644
--- a/server.go
+++ b/server.go
@@ -152,23 +152,23 @@ func getCategories(rw http.ResponseWriter, req *http.Request) {
 }
 
 func addCategory(rw http.ResponseWriter, req *http.Request) {
-	type jsonRequest struct {
+	type jsonAddCategoryRequest struct {
 		Description string `json:"description"`
 	}
 
-	type jsonResponse struct {
+	type jsonAddCategoryResponse struct {
 		Description string `json:"description"`
 		Id          int    `json:"id"`
 		Success     bool   `json:"success"`
 	}
 
-	var request jsonRequest
+	var request jsonAddCategoryRequest
 	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
 		http.Error(rw, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
-	response := jsonResponse{Description: strings.TrimSpace(request.Description)}
+	response := jsonAddCategoryResponse{Description: strings.TrimSpace(request.Description)}
 
 	if len(request.Description) > 0 {
 		result, err := db.Exec("INSERT INTO categories(description) VALUES(?)", request.Description)
@@ -200,15 +200,15 @@ func addCategory(rw http.ResponseWriter, req *http.Request) {
 }
 
 func removeCategory(rw http.ResponseWriter, req *http.Request) {
-	type jsonRequest struct {
+	type jsonRemoveCategoryRequest struct {
 		Id int `json:"id"`
 	}
 
-	type jsonResponse struct {
+	type jsonRemoveCategoryResponse struct {
 		Success bool `json:"success"`
 	}
 
-	var request jsonRequest
+	var request jsonRemoveCategoryRequest
 	if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
 		http.Error(rw, err.Error(), http.StatusInternalServerError)
 		return
@@ -224,7 +224,7 @@ func removeCategory(rw http.ResponseWriter, req *http.Request) {
 		log.Fatal(err)
 	}
 
-	js, err := json.Marshal(jsonResponse{affectedRows > 0})
+	js, err := json.Marshal(jsonRemoveCategoryResponse{affectedRows > 0})
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/types.go b/types.go
index 4e25d2c..40aba1b 100644
--- a/types.go
+++ b/types.go
@@ -35,8 +35,6 @@ type queryProjection struct {
 	stats  recordStats
 }
 
-type featureMap map[interface{}]float64
-
 type recordStats struct {
 	compatibility float64
 	count         int
@@ -78,3 +76,5 @@ func (slice records) Less(i, j int) bool {
 func (slice records) Swap(i, j int) {
 	slice[i], slice[j] = slice[j], slice[i]
 }
+
+type featureMap map[interface{}]float64