diff --git a/src/constants.h b/src/constants.h
new file mode 100644
index 00000000..04fa9e5d
--- /dev/null
+++ b/src/constants.h
@@ -0,0 +1,10 @@
+#ifndef LIBPOSTAL_CONSTANTS_H
+#define LIBPOSTAL_CONSTANTS_H
+
+#include <stdlib.h>
+#include <string.h>
+
+#define NAMESPACE_SEPARATOR_CHAR "|"
+#define NAMESPACE_SEPARATOR_CHAR_LEN strlen(NAMESPACE_SEPARATOR_CHAR)
+
+#endif
\ No newline at end of file