diff --git a/cmd/ubsserver/main.go b/cmd/ubsserver/main.go
index c2381ac..ffbf7b2 100644
--- a/cmd/ubsserver/main.go
+++ b/cmd/ubsserver/main.go
@@ -76,7 +76,18 @@ func info(w http.ResponseWriter, req *http.Request) {
 	}
 }
 
+func ensureJSONRequest(w http.ResponseWriter, req *http.Request) bool {
+	if strings.ToLower(req.Header["Content-Type"][0]) != "application/json" {
+		sendJSONError(w, syncstore.RequiredDataNotFoundError)
+		return false
+	}
+	return true
+}
+
 func createSync(w http.ResponseWriter, req *http.Request) {
+	if !ensureJSONRequest(w, req) {
+		return
+	}
 	body := new(syncstore.CreateReq)
 	req.Body = http.MaxBytesReader(w, req.Body, 10000)
 	err := json.NewDecoder(req.Body).Decode(&body)
@@ -124,6 +135,9 @@ func getVersion(syncId string, w http.ResponseWriter, _ *http.Request) {
 }
 
 func updateSync(syncId string, w http.ResponseWriter, req *http.Request) {
+	if !ensureJSONRequest(w, req) {
+		return
+	}
 	body := new(syncstore.UpdateReq)
 	req.Body = http.MaxBytesReader(w, req.Body, int64(10000 + maxSyncSize))
 	err := json.NewDecoder(req.Body).Decode(&body)
diff --git a/syncstore/errors.go b/syncstore/errors.go
index 7755a68..5b52ade 100644
--- a/syncstore/errors.go
+++ b/syncstore/errors.go
@@ -52,4 +52,9 @@ var (
 		"SyncDataLimitExceededException",
 		"Sync data limit exceeded",
 		http.StatusRequestEntityTooLarge)
+
+	RequiredDataNotFoundError = NewSyncError(
+		"RequiredDataNotFoundException",
+		"Unable to find required data",
+		http.StatusBadRequest)
 )