diff --git a/api/check_examples.py b/api/check_examples.py
new file mode 100755
index 00000000..00e75263
--- /dev/null
+++ b/api/check_examples.py
@@ -0,0 +1,84 @@
+#! /usr/bin/env python
+
+import sys
+import json
+import os
+
+
+def import_error(module, package, debian, error):
+    sys.stderr.write((
+        "Error importing %(module)s: %(error)r\n"
+        "To install %(module)s run:\n"
+        "  pip install %(package)s\n"
+        "or on Debian run:\n"
+        "  sudo apt-get install python-%(debian)s\n"
+    ) % locals())
+    if __name__ == '__main__':
+        sys.exit(1)
+
+try:
+    import jsonschema
+except ImportError as e:
+    import_error("jsonschema", "jsonschema", "jsonschema", e)
+    raise
+
+try:
+    import yaml
+except ImportError as e:
+    import_error("yaml", "PyYAML", "yaml", e)
+    raise
+
+
+def check_response(filepath, request, code, response):
+    example = None
+    try:
+        example_json = response.get('examples', {}).get('application/json')
+        if example_json:
+            example = json.loads(example_json)
+    except Exception as e:
+        raise ValueError("Error parsing JSON example response for %r %r" % (
+            request, code
+        ), e)
+    schema = response.get('schema')
+    fileurl = "file://" + os.path.abspath(filepath)
+    if example and schema:
+        try:
+            print ("Checking schema for: %r %r %r" % (filepath, request, code))
+            # Setting the 'id' tells jsonschema where the file is so that it
+            # can correctly resolve relative $ref references in the schema
+            schema['id'] = fileurl
+            jsonschema.validate(example, schema)
+        except Exception as e:
+            raise ValueError("Error validating JSON schema for %r %r" % (
+                request, code
+            ), e)
+
+
+def check_swagger_file(filepath):
+    with open(filepath) as f:
+        swagger = yaml.load(f)
+
+    for path, path_api in swagger.get('paths', {}).items():
+        for method, request_api in path_api.items():
+            request = "%s %s" % (method.upper(), path)
+            try:
+                responses = request_api['responses']
+            except KeyError:
+                raise ValueError("No responses for %r" % (request,))
+            for code, response in responses.items():
+                check_response(filepath, request, code, response)
+
+
+if __name__ == '__main__':
+    paths = sys.argv[1:]
+    if not paths:
+        paths = []
+        for (root, dirs, files) in os.walk(os.curdir):
+            for filename in files:
+                if filename.endswith(".yaml"):
+                    paths.append(os.path.join(root, filename))
+    for path in paths:
+        try:
+            check_swagger_file(path)
+        except Exception as e:
+            raise ValueError("Error checking file %r" % (path,), e)
diff --git a/api/client-server/v1/presence.yaml b/api/client-server/v1/presence.yaml
index 717e9c47..5684398b 100644
--- a/api/client-server/v1/presence.yaml
+++ b/api/client-server/v1/presence.yaml
@@ -101,7 +101,7 @@ paths:
                   The length of time in milliseconds since an action was performed
                   by this user.
               status_msg:
-                type: string
+                type: [string, "null"]
                 description: The state message for this user if one was set.
         404:
           description: |-
@@ -185,7 +185,7 @@ paths:
                     "last_active_ago": 395,
                     "presence": "offline",
                     "user_id": "@alice:matrix.org"
-                  }
+                  },
                   "type": "m.presence"
                 },
                 {
@@ -195,7 +195,7 @@ paths:
                     "last_active_ago": 16874,
                     "presence": "online",
                     "user_id": "@marisa:matrix.org"
-                  }
+                  },
                   "type": "m.presence"
                 }
               ]
diff --git a/api/client-server/v1/sync.yaml b/api/client-server/v1/sync.yaml
index 27c7073c..833c425a 100644
--- a/api/client-server/v1/sync.yaml
+++ b/api/client-server/v1/sync.yaml
@@ -343,7 +343,7 @@ paths:
                   "body": "Hello world!",
                   "msgtype": "m.text"
                 },
-                "room_id:" "!wfgy43Sg4a:matrix.org",
+                "room_id:": "!wfgy43Sg4a:matrix.org",
                 "user_id": "@bob:matrix.org",
                 "event_id": "$asfDuShaf7Gafaw:matrix.org",
                 "type": "m.room.message"
diff --git a/templating/matrix_templates/units.py b/templating/matrix_templates/units.py
index 9ee14598..1a9d981a 100644
--- a/templating/matrix_templates/units.py
+++ b/templating/matrix_templates/units.py
@@ -97,6 +97,8 @@ def get_json_schema_object_fields(obj, enforce_title=False):
                     desc += (
                         " Must be '%s'." % props[key_name]["enum"][0]
                     )
+            if isinstance(value_type, list):
+                value_type = " or ".join(value_type)
 
         fields["rows"].append({
             "key": key_name,