diff --git a/halfapi/__init__.py b/halfapi/__init__.py
index 2d7d3d1..60d04d4 100644
--- a/halfapi/__init__.py
+++ b/halfapi/__init__.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-__version__ = '0.6.22-rc0'
+__version__ = '0.6.22-rc1'
 
 def version():
     return f'HalfAPI version:{__version__}'
diff --git a/halfapi/lib/domain.py b/halfapi/lib/domain.py
index b90b0f6..1c61d1a 100644
--- a/halfapi/lib/domain.py
+++ b/halfapi/lib/domain.py
@@ -52,7 +52,7 @@ class NoDomainsException(Exception):
     """
     pass
 
-def route_decorator(fct: FunctionType, ret_type: str = 'json') -> Coroutine:
+def route_decorator(fct: FunctionType) -> Coroutine:
     """ Returns an async function that can be mounted on a router
     """
     @wraps(fct)
@@ -60,9 +60,10 @@ def route_decorator(fct: FunctionType, ret_type: str = 'json') -> Coroutine:
     async def wrapped(request, *args, **kwargs):
         fct_args_spec = inspect.getfullargspec(fct).args
         fct_args_defaults = inspect.getfullargspec(fct).defaults or []
-        fct_args_defaults_dict = {}
-        for i in range(len(fct_args_defaults)):
-            fct_args_defaults_dict[fct_args_spec[-i]] = fct_args_defaults[-i]
+        fct_args_defaults_dict = dict(list(zip(
+            reversed(fct_args_spec),
+            reversed(fct_args_defaults)
+        )))
 
         fct_args = request.path_params.copy()
 
@@ -76,7 +77,12 @@ def route_decorator(fct: FunctionType, ret_type: str = 'json') -> Coroutine:
 
 
         if 'data' in fct_args_spec:
-            fct_args['data'] = kwargs.get('data')
+            if 'data' in fct_args_defaults_dict:
+                fct_args['data'] = fct_args_defaults_dict
+            else:
+                fct_args['data'] = {}
+
+            fct_args['data'].update(kwargs.get('data', {}))
 
         if 'out' in fct_args_spec:
             fct_args['out'] = kwargs.get('out')
@@ -88,6 +94,8 @@ def route_decorator(fct: FunctionType, ret_type: str = 'json') -> Coroutine:
         else:
             ret_type = fct_args.get('data', {}).get('format', 'json')
 
+        logger.debug('Return type {} (defaults: {})'.format(ret_type,
+            fct_args_defaults_dict))
         try:
             if ret_type == 'json':
                 return ORJSONResponse(fct(**fct_args))
diff --git a/tests/dummy_domain/routers/ret_type/EXT_str/__init__.py b/tests/dummy_domain/routers/ret_type/EXT_str/__init__.py
new file mode 100644
index 0000000..380b048
--- /dev/null
+++ b/tests/dummy_domain/routers/ret_type/EXT_str/__init__.py
@@ -0,0 +1,13 @@
+from halfapi.lib import acl
+
+ACLS = {
+    'GET': [{'acl':acl.public}]
+}
+
+def get(ext, ret_type='html'):
+    """
+    responses:
+      200:
+        description: dummy abc.alphabet route
+    """
+    return '\n'.join(('trololo', '', 'ololotr'))
diff --git a/tests/dummy_domain/routers/ret_type/EXT_str/config/__init__.py b/tests/dummy_domain/routers/ret_type/EXT_str/config/__init__.py
new file mode 100644
index 0000000..639e3ea
--- /dev/null
+++ b/tests/dummy_domain/routers/ret_type/EXT_str/config/__init__.py
@@ -0,0 +1,31 @@
+from halfapi.lib import acl
+
+ACLS = {
+    'GET': [{'acl':acl.public}],
+    'POST': [
+        {
+            'acl':acl.public,
+            'args': {
+                'required': {'trou'},
+                'optional': {'troo'}
+            }
+        }
+    ]
+}
+
+def get(ext, halfapi={}, ret_type='html'):
+    """
+    responses:
+      200:
+        description: dummy abc.alphabet route
+    """
+    return '\n'.join(('trololo', '', 'ololotr'))
+
+def post(ext, data={'troo': 'fidget'}, halfapi={}, ret_type='html'):
+    """
+    responses:
+      200:
+        description: dummy abc.alphabet route
+    """
+    print(data)
+    return '\n'.join(('trololo', '', 'ololotr'))
diff --git a/tests/test_domain.py b/tests/test_domain.py
index e84a832..d3ad4f9 100644
--- a/tests/test_domain.py
+++ b/tests/test_domain.py
@@ -19,3 +19,20 @@ class TestDummyDomain(TestDomain):
         assert res.status_code == 200
         assert isinstance(res.content.decode(), str)
         assert res.headers['content-type'].split(';')[0] == 'text/html'
+
+        res = self.client.get('/ret_type/h24')
+        assert res.status_code == 200
+        assert isinstance(res.content.decode(), str)
+        assert res.headers['content-type'].split(';')[0] == 'text/html'
+
+        res = self.client.get('/ret_type/h24/config')
+        assert res.status_code == 200
+        assert isinstance(res.content.decode(), str)
+        assert res.headers['content-type'].split(';')[0] == 'text/html'
+
+        res = self.client.post('/ret_type/h24/config', {
+            'trou': 'glet'
+        })
+        assert res.status_code == 200
+        assert isinstance(res.content.decode(), str)
+        assert res.headers['content-type'].split(';')[0] == 'text/html'