diff --git a/README.md b/README.md
index 61956894b..26c2431fb 100644
--- a/README.md
+++ b/README.md
@@ -124,6 +124,8 @@ The JSON should follow the structure:
                   "max": Integer, // numeric only
                   "step": Integer, // numeric only
                   "width": 2 / 3 / 4 / 5 / 10 / 20, // text and numeric only
+                  "prefix": String, // numeric only
+                  "suffix": String, //numeric only
                   "answer_options": { // checkbox and radio only
                     "0": String,
                     "1": String