diff --git a/tests/test_xrpc_actor.py b/tests/test_xrpc_actor.py
index 36f56a4..de89dcd 100644
--- a/tests/test_xrpc_actor.py
+++ b/tests/test_xrpc_actor.py
@@ -48,6 +48,10 @@ class XrpcActorTest(testutil.TestCase):
             },
         }, resp.json)
 
+    def test_getProfile_unset(self, _):
+        resp = self.client.get('/xrpc/app.bsky.actor.getProfile')
+        self.assertEqual(400, resp.status_code)
+
     def test_getProfile_not_domain(self, _):
         resp = self.client.get('/xrpc/app.bsky.actor.getProfile',
                                query_string={'actor': 'not a domain'})
diff --git a/tests/test_xrpc_feed.py b/tests/test_xrpc_feed.py
index 820fe5e..b4e13ab 100644
--- a/tests/test_xrpc_feed.py
+++ b/tests/test_xrpc_feed.py
@@ -100,6 +100,10 @@ class XrpcFeedTest(testutil.TestCase):
             'feed': [POST_BSKY, REPLY_BSKY, REPOST_BSKY],
         }, resp.json)
 
+    def test_getAuthorFeed_unset(self, _):
+        resp = self.client.get('/xrpc/app.bsky.feed.getAuthorFeed')
+        self.assertEqual(400, resp.status_code)
+
     def test_getAuthorFeed_not_domain(self, _):
         resp = self.client.get('/xrpc/app.bsky.feed.getAuthorFeed',
                                query_string={'author': 'not a domain'})
@@ -127,6 +131,10 @@ class XrpcFeedTest(testutil.TestCase):
         self.assertEqual(200, resp.status_code, resp.get_data(as_text=True))
         self.assert_equals(POST_THREAD_BSKY, resp.json)
 
+    def test_getPostThread_unset(self, mock_get):
+        mock_get.return_value = requests_response(status=500)
+        resp = self.client.get('/xrpc/app.bsky.feed.getPostThread')
+        self.assertEqual(400, resp.status_code)
 
     def test_getPostThread_fetch_fails(self, mock_get):
         mock_get.return_value = requests_response(status=500)
diff --git a/xrpc_actor.py b/xrpc_actor.py
index 21f53ce..e7abca6 100644
--- a/xrpc_actor.py
+++ b/xrpc_actor.py
@@ -19,7 +19,7 @@ def getProfile(input, actor=None):
     """
     # TODO: actor is either handle or DID
     # see actorWhereClause in atproto/packages/pds/src/db/util.ts
-    if not re.match(util.DOMAIN_RE, actor):
+    if not actor or not re.match(util.DOMAIN_RE, actor):
         raise ValueError(f'{actor} is not a domain')
 
     url = f'https://{actor}/'
diff --git a/xrpc_feed.py b/xrpc_feed.py
index cbde751..1016b9e 100644
--- a/xrpc_feed.py
+++ b/xrpc_feed.py
@@ -18,7 +18,7 @@ def getAuthorFeed(input, author=None, limit=None, before=None):
     """
     lexicons/app/bsky/feed/getAuthorFeed.json, feedViewPost.json
     """
-    if not re.match(util.DOMAIN_RE, author):
+    if not author or not re.match(util.DOMAIN_RE, author):
         raise ValueError(f'{author} is not a domain')
 
     url = f'https://{author}/'
@@ -54,6 +54,9 @@ def getPostThread(input, uri=None, depth=None):
     """
     lexicons/app/bsky/feed/getPostThread.json
     """
+    if not uri:
+        raise ValueError('Missing uri')
+
     mf2 = util.fetch_mf2(uri, gateway=True)
     logger.info(f'Got mf2: {json.dumps(mf2, indent=2)}')