diff --git a/publish.py b/publish.py
index 9e7a09b..11a7aec 100644
--- a/publish.py
+++ b/publish.py
@@ -65,7 +65,8 @@ def is_data_equal(old, new):
 
 
 def should_publish_data():
-    current_contents = json.load(open('service-types.json'))
+    with open('service-types.json') as fh:
+        current_contents = json.load(fh)
 
     try:
         response = requests.get(HTTP_LOCATION)
@@ -73,8 +74,9 @@ def should_publish_data():
         existing_contents = response.json()
     except (requests.HTTPError, requests.ConnectionError) as e:
         print(
-            'Failed to fetch current service-types.json. Assuming data'
-            f' needs to be published. Error: {str(e)}'
+            f'Failed to fetch current service-types.json. Assuming data '
+            f'needs to be published. Error: {str(e)}',
+            file=sys.stderr,
         )
         return (True, current_contents['version'])
 
@@ -95,7 +97,10 @@ def main():
     if not os.path.exists(OUTDIR):
         os.makedirs(OUTDIR)
     elif not os.path.isdir(OUTDIR):
-        print(f'{OUTDIR} exists but is not a directory. Aborting!')
+        print(
+            f'{OUTDIR} exists but is not a directory. Aborting!',
+            file=sys.stderr,
+        )
         return 1
 
     # It's fine to always copy the json schema
@@ -109,8 +114,9 @@ def main():
         to_copy += glob.glob('service-types.json*')
     else:
         print(
-            f'Data in existing file matches {latest_version} data.'
-            ' Not publishing'
+            f'Data in existing file matches {latest_version} data. '
+            f'Not publishing',
+            file=sys.stderr,
         )
 
     for filename in to_copy:
diff --git a/transform.py b/transform.py
index a74439e..dcf78dc 100644
--- a/transform.py
+++ b/transform.py
@@ -43,8 +43,8 @@ def create_local_registry():
         if uri.startswith('https://specs.openstack.org'):
             # The URI arrives with fragment removed. We assume no querystring.
             filename = uri.split('/')[-1]
-            with open(filename) as f:
-                return referencing.Resource.from_contents(json.load(f))
+            with open(filename) as fh:
+                return referencing.Resource.from_contents(json.load(fh))
         # We shouldn't have any external URIs. Scream bloody murder if someone
         # tries.
         raise referencing.exceptions.NoSuchResource(ref=uri)
@@ -80,7 +80,8 @@ def main():
     )
     args = parser.parse_args()
 
-    mapping = yaml.safe_load(open('service-types.yaml'))
+    with open('service-types.yaml') as fh:
+        mapping = yaml.safe_load(fh)
 
     # we are using a TZ-naive timestamp for legacy reasons, but we should
     # probably revisit this as TZ-naive timestamps are a menace
@@ -124,7 +125,9 @@ def main():
         if not service.get('api_reference'):
             service['api_reference'] = API_REF_FMT.format(service=service_type)
 
-    schema = json.load(open('published-schema.json'))
+    with open('published-schema.json') as fh:
+        schema = json.load(fh)
+
     registry = create_local_registry()
 
     valid = validate.validate_all(schema, mapping, registry=registry)
@@ -133,11 +136,10 @@ def main():
         output = json.dumps(mapping, indent=2, sort_keys=True)
         output.replace(' \n', '\n')
         unversioned_filename = 'service-types.json'
-        versioned_filename = 'service-types.json.{version}'.format(
-            version=mapping['version']
-        )
+        versioned_filename = f'service-types.json.{mapping["version"]}'
         for filename in (unversioned_filename, versioned_filename):
-            open(filename, 'w').write(output)
+            with open(filename, 'w') as fh:
+                fh.write(output)
 
     return int(not valid)
 
diff --git a/validate.py b/validate.py
index 168bc63..e1e267a 100644
--- a/validate.py
+++ b/validate.py
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import sys
+
 import jsonschema
 
 
@@ -44,8 +46,9 @@ def validate_unique_tokens(data):
         if service.get('secondary', False):
             continue
         if service['project'] in projects:
-            yield "'{service}' is duplicate service from '{project}'".format(
-                service=service['service_type'], project=service['project']
+            yield (
+                f"'{service['service_type']}' duplicates service from "
+                f"'{service['project']}'"
             )
         projects.append(service['project'])
     for alias in aliases:
@@ -54,15 +57,15 @@ def validate_unique_tokens(data):
 
 
 def validate_all(schema, data, registry):
-    """Runs all validators, printing any errors to stdout.
+    """Runs all validators, printing any errors to stderr.
 
     :return: True if all checks passed; False if any checks failed.
     """
     ret = True
     for msg in validate_schema(schema, data, registry):
-        print(msg)
+        print(msg, file=sys.stderr)
         ret = False
     for msg in validate_unique_tokens(data):
-        print(msg)
+        print(msg, file=sys.stderr)
         ret = False
     return ret