odd cut and paste error fixed.

freqtrade/constants.py

@@ -124,6 +124,7 @@ CONF_SCHEMA = {
             'type': 'object',
             'properties': {
                 'name': {'type': 'string'},
+                'sandbox': {'type': 'boolean'},
                 'key': {'type': 'string'},
                 'secret': {'type': 'string'},
                 'pair_whitelist': {

freqtrade/exchange/__init__.py

@@ -95,6 +95,11 @@ class Exchange(object):
         except (KeyError, AttributeError):
             raise OperationalException(f'Exchange {name} is not supported')
 
+        # check if config requests sanbox, if so use ['test'] from url
+        if (exchange_config.get('sandbox')):
+            api.urls['api'] = api.urls['test'];
+            # exchange.urls['api'] = exchange.urls['test'];
+
         return api
 
     @property