diff --git a/src/rpc/util.h b/src/rpc/util.h
--- a/src/rpc/util.h
+++ b/src/rpc/util.h
@@ -106,6 +106,8 @@
         AMOUNT,
         //! Special type that is a STR with only hex chars
         STR_HEX,
+        //! Special type that is a NUM or [NUM,NUM]
+        RANGE,
     };
 
     enum class Optional {
diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -337,6 +337,7 @@
             case RPCArg::Type::STR:
             case RPCArg::Type::NUM:
             case RPCArg::Type::AMOUNT:
+            case RPCArg::Type::RANGE:
             case RPCArg::Type::BOOL: {
                 // Nothing more to do for non-recursive types on first recursion
                 if (outer_type == OuterType::NAMED_ARG) {
@@ -566,6 +567,10 @@
                 ret += "numeric or string";
                 break;
             }
+            case Type::RANGE: {
+                ret += "numeric or array";
+                break;
+            }
             case Type::BOOL: {
                 ret += "boolean";
                 break;
@@ -625,6 +630,8 @@
             return res + "\"hex\"";
         case Type::NUM:
             return res + "n";
+        case Type::RANGE:
+            return res + "n or [n,n]";
         case Type::AMOUNT:
             return res + "amount";
         case Type::BOOL:
@@ -656,6 +663,7 @@
             return "\"" + m_name + "\"";
         }
         case Type::NUM:
+        case Type::RANGE:
         case Type::AMOUNT:
         case Type::BOOL: {
             return m_name;