diff --git a/apps/json/json.h b/apps/json/json.h
index a698464a5..d91cf93ef 100644
--- a/apps/json/json.h
+++ b/apps/json/json.h
@@ -45,6 +45,7 @@
 #define JSON_TYPE_PAIR ':'
 #define JSON_TYPE_PAIR_NAME 'N' /* for N:V pairs */
 #define JSON_TYPE_STRING '"'
+#define JSON_TYPE_UINT 'U'
 #define JSON_TYPE_INT 'I'
 #define JSON_TYPE_NUMBER '0'
 #define JSON_TYPE_ERROR 0
diff --git a/apps/json/jsontree.c b/apps/json/jsontree.c
index e397ae47b..4ffe68161 100644
--- a/apps/json/jsontree.c
+++ b/apps/json/jsontree.c
@@ -79,16 +79,11 @@ jsontree_write_string(const struct jsontree_context *js_ctx, const char *text)
 }
 /*---------------------------------------------------------------------------*/
 void
-jsontree_write_int(const struct jsontree_context *js_ctx, int value)
+jsontree_write_uint(const struct jsontree_context *js_ctx, unsigned int value)
 {
   char buf[10];
   int l;
 
-  if(value < 0) {
-    js_ctx->putchar('-');
-    value = -value;
-  }
-
   l = sizeof(buf) - 1;
   do {
     buf[l--] = '0' + (value % 10);
@@ -101,6 +96,17 @@ jsontree_write_int(const struct jsontree_context *js_ctx, int value)
 }
 /*---------------------------------------------------------------------------*/
 void
+jsontree_write_int(const struct jsontree_context *js_ctx, int value)
+{
+  if(value < 0) {
+    js_ctx->putchar('-');
+    value = -value;
+  }
+
+  jsontree_write_uint(js_ctx, value);
+}
+/*---------------------------------------------------------------------------*/
+void
 jsontree_setup(struct jsontree_context *js_ctx, struct jsontree_value *root,
                int (* putchar)(int))
 {
@@ -203,6 +209,10 @@ jsontree_print_next(struct jsontree_context *js_ctx)
     jsontree_write_string(js_ctx, ((struct jsontree_string *)v)->value);
     /* Default operation: back up one level! */
     break;
+  case JSON_TYPE_UINT:
+    jsontree_write_uint(js_ctx, ((struct jsontree_uint *)v)->value);
+    /* Default operation: back up one level! */
+    break;
   case JSON_TYPE_INT:
     jsontree_write_int(js_ctx, ((struct jsontree_int *)v)->value);
     /* Default operation: back up one level! */
diff --git a/apps/json/jsontree.h b/apps/json/jsontree.h
index b378d36b5..3434565a2 100644
--- a/apps/json/jsontree.h
+++ b/apps/json/jsontree.h
@@ -74,6 +74,11 @@ struct jsontree_string {
   const char *value;
 };
 
+struct jsontree_uint {
+  uint8_t type;
+  unsigned int value;
+};
+
 struct jsontree_int {
   uint8_t type;
   int value;
@@ -136,6 +141,8 @@ void jsontree_reset(struct jsontree_context *js_ctx);
 const char *jsontree_path_name(const struct jsontree_context *js_ctx,
                                int depth);
 
+void jsontree_write_uint(const struct jsontree_context *js_ctx,
+                         unsigned int value);
 void jsontree_write_int(const struct jsontree_context *js_ctx, int value);
 void jsontree_write_atom(const struct jsontree_context *js_ctx,
                          const char *text);