diff --git a/frontend/submit.go b/frontend/submit.go
index 2b66f644..51dd2583 100644
--- a/frontend/submit.go
+++ b/frontend/submit.go
@@ -20,10 +20,10 @@ func (SubmissionHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 	// Check request type and size
 	if r.Method != "POST" {
-		http.Error(w, "{errmsg:\"Bad request.\"}", http.StatusBadRequest)
+		http.Error(w, "{\"errmsg\":\"Bad request.\"}", http.StatusBadRequest)
 		return
 	} else if r.ContentLength < 0 || r.ContentLength > 255 {
-		http.Error(w, "{errmsg:\"Request too large or request size unknown\"}", http.StatusRequestEntityTooLarge)
+		http.Error(w, "{\"errmsg\":\"Request too large or request size unknown\"}", http.StatusRequestEntityTooLarge)
 		return
 	}
 
@@ -32,23 +32,23 @@ func (SubmissionHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	var sURL = strings.Split(r.URL.Path, "/")
 
 	if len(sURL) != 3 && len(sURL) != 4 {
-		http.Error(w, "{errmsg:\"Bad request.\"}", http.StatusBadRequest)
+		http.Error(w, "{\"errmsg\":\"Bad request.\"}", http.StatusBadRequest)
 		return
 	}
 
 	// Parse arguments
 	if team, err := strconv.Atoi(sURL[1]); err != nil {
-		http.Error(w, "{errmsg:\"Bad request.\"}", http.StatusBadRequest)
+		http.Error(w, "{\"errmsg\":\"Bad request.\"}", http.StatusBadRequest)
 		return
 	} else if exercice, err := strconv.Atoi(sURL[2]); err != nil {
-		http.Error(w, "{errmsg:\"Bad request.\"}", http.StatusBadRequest)
+		http.Error(w, "{\"errmsg\":\"Bad request.\"}", http.StatusBadRequest)
 		return
 	} else {
 		if _, err := os.Stat(path.Join(SubmissionDir, fmt.Sprintf("%d", team))); os.IsNotExist(err) {
 			log.Println("Creating submission directory for", team)
 			if err := os.MkdirAll(path.Join(SubmissionDir, fmt.Sprintf("%d", team)), 0777); err != nil {
 				log.Println("Unable to create submission directory: ", err)
-				http.Error(w, "{errmsg:\"Internal server error. Please retry in few seconds.\"}", http.StatusInternalServerError)
+				http.Error(w, "{\"errmsg\":\"Internal server error. Please retry in few seconds.\"}", http.StatusInternalServerError)
 				return
 			}
 		}
@@ -56,7 +56,7 @@ func (SubmissionHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 		// Previous submission not treated
 		if _, err := os.Stat(path.Join(SubmissionDir, fmt.Sprintf("%d", team), fmt.Sprintf("%d", exercice))); !os.IsNotExist(err) {
-			http.Error(w, "{errmsg:\"Calm-down. A solution is already being processed.\"}", http.StatusPaymentRequired)
+			http.Error(w, "{\"errmsg\":\"Calm-down. A solution is already being processed.\"}", http.StatusPaymentRequired)
 			return
 		}
 
@@ -80,12 +80,12 @@ func (SubmissionHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		// Store content in file
 		if file, err := os.Create(path.Join(SubmissionDir, fmt.Sprintf("%d", team), fmt.Sprintf("%d", exercice))); err != nil {
 			log.Println("Unable to open exercice file:", err)
-			http.Error(w, "{errmsg:\"Internal server error. Please retry in few seconds.\"}", http.StatusInternalServerError)
+			http.Error(w, "{\"errmsg\":\"Internal server error. Please retry in few seconds.\"}", http.StatusInternalServerError)
 			return
 		} else {
 			file.Write(body)
 			file.Close()
 		}
-		http.Error(w, "{errmsg:\"Submission accepted, please wait...\"}", http.StatusAccepted)
+		http.Error(w, "{\"errmsg\":\"Submission accepted, please wait...\"}", http.StatusAccepted)
 	}
 }