diff --git a/mistral/api/controllers/resource.py b/mistral/api/controllers/resource.py
index 4052a1d53..af7b16f9f 100644
--- a/mistral/api/controllers/resource.py
+++ b/mistral/api/controllers/resource.py
@@ -58,7 +58,7 @@ class Resource(wtypes.Base):
 
         return res + "]"
 
-    def to_string(self):
+    def to_json(self):
         return json.dumps(self.to_dict())
 
     @classmethod
diff --git a/mistral/api/controllers/v2/action.py b/mistral/api/controllers/v2/action.py
index 4e4d87196..29bd6551c 100644
--- a/mistral/api/controllers/v2/action.py
+++ b/mistral/api/controllers/v2/action.py
@@ -135,7 +135,7 @@ class ActionsController(rest.RestController, hooks.HookController):
 
         action_list = [Action.from_dict(act) for act in models_dicts]
 
-        return Actions(actions=action_list).to_string()
+        return Actions(actions=action_list).to_json()
 
     @rest_utils.wrap_pecan_controller_exception
     @pecan.expose(content_type="text/plain")
@@ -163,7 +163,7 @@ class ActionsController(rest.RestController, hooks.HookController):
 
         action_list = [Action.from_dict(act) for act in models_dicts]
 
-        return Actions(actions=action_list).to_string()
+        return Actions(actions=action_list).to_json()
 
     @rest_utils.wrap_wsme_controller_exception
     @wsme_pecan.wsexpose(None, wtypes.text, status_code=204)
diff --git a/mistral/api/controllers/v2/workbook.py b/mistral/api/controllers/v2/workbook.py
index 961b2a899..08123d9bd 100644
--- a/mistral/api/controllers/v2/workbook.py
+++ b/mistral/api/controllers/v2/workbook.py
@@ -99,7 +99,7 @@ class WorkbooksController(rest.RestController, hooks.HookController):
 
         wb_db = workbooks.update_workbook_v2(definition)
 
-        return Workbook.from_dict(wb_db.to_dict()).to_string()
+        return Workbook.from_dict(wb_db.to_dict()).to_json()
 
     @rest_utils.wrap_pecan_controller_exception
     @pecan.expose(content_type="text/plain")
@@ -112,7 +112,7 @@ class WorkbooksController(rest.RestController, hooks.HookController):
         wb_db = workbooks.create_workbook_v2(definition)
         pecan.response.status = 201
 
-        return Workbook.from_dict(wb_db.to_dict()).to_string()
+        return Workbook.from_dict(wb_db.to_dict()).to_json()
 
     @rest_utils.wrap_wsme_controller_exception
     @wsme_pecan.wsexpose(None, wtypes.text, status_code=204)
diff --git a/mistral/api/controllers/v2/workflow.py b/mistral/api/controllers/v2/workflow.py
index c80d671c9..bfcc65fb1 100644
--- a/mistral/api/controllers/v2/workflow.py
+++ b/mistral/api/controllers/v2/workflow.py
@@ -193,8 +193,8 @@ class WorkflowsController(rest.RestController, hooks.HookController):
         models_dicts = [db_wf.to_dict() for db_wf in db_wfs]
         workflow_list = [Workflow.from_dict(wf) for wf in models_dicts]
 
-        return (workflow_list[0].to_string() if identifier
-                else Workflows(workflows=workflow_list).to_string())
+        return (workflow_list[0].to_json() if identifier
+                else Workflows(workflows=workflow_list).to_json())
 
     @rest_utils.wrap_pecan_controller_exception
     @pecan.expose(content_type="text/plain")
@@ -222,7 +222,7 @@ class WorkflowsController(rest.RestController, hooks.HookController):
 
         workflow_list = [Workflow.from_dict(wf) for wf in models_dicts]
 
-        return Workflows(workflows=workflow_list).to_string()
+        return Workflows(workflows=workflow_list).to_json()
 
     @rest_utils.wrap_wsme_controller_exception
     @wsme_pecan.wsexpose(None, wtypes.text, status_code=204)
diff --git a/mistral/tests/unit/api/v2/test_environment.py b/mistral/tests/unit/api/v2/test_environment.py
index 92b823fc5..28d7d7cb9 100644
--- a/mistral/tests/unit/api/v2/test_environment.py
+++ b/mistral/tests/unit/api/v2/test_environment.py
@@ -121,7 +121,7 @@ def _convert_vars_to_dict(env_dict):
     return env_dict
 
 
-def _convert_vars_to_string(env_dict):
+def _convert_vars_to_json(env_dict):
     """Converts 'variables' in the given environment dict into string."""
     if ('variables' in env_dict and
             isinstance(env_dict.get('variables'), dict)):
@@ -179,7 +179,7 @@ class TestEnvironmentController(base.APITest):
     def test_post(self):
         resp = self.app.post_json(
             '/v2/environments',
-            _convert_vars_to_string(copy.deepcopy(ENVIRONMENT_FOR_CREATE))
+            _convert_vars_to_json(copy.deepcopy(ENVIRONMENT_FOR_CREATE))
         )
 
         self.assertEqual(201, resp.status_int)
@@ -190,7 +190,7 @@ class TestEnvironmentController(base.APITest):
     def test_post_with_illegal_field(self):
         resp = self.app.post_json(
             '/v2/environments',
-            _convert_vars_to_string(
+            _convert_vars_to_json(
                 copy.deepcopy(ENVIRONMENT_WITH_ILLEGAL_FIELD)),
             expect_errors=True
         )
@@ -200,7 +200,7 @@ class TestEnvironmentController(base.APITest):
     def test_post_dup(self):
         resp = self.app.post_json(
             '/v2/environments',
-            _convert_vars_to_string(copy.deepcopy(ENVIRONMENT_FOR_CREATE)),
+            _convert_vars_to_json(copy.deepcopy(ENVIRONMENT_FOR_CREATE)),
             expect_errors=True
         )
 
@@ -208,7 +208,7 @@ class TestEnvironmentController(base.APITest):
 
     @mock.patch.object(db_api, 'create_environment', MOCK_ENVIRONMENT)
     def test_post_default_scope(self):
-        env = _convert_vars_to_string(copy.deepcopy(ENVIRONMENT_FOR_CREATE))
+        env = _convert_vars_to_json(copy.deepcopy(ENVIRONMENT_FOR_CREATE))
 
         resp = self.app.post_json('/v2/environments', env)