diff --git a/common.py b/common.py
index b498128..70ee045 100644
--- a/common.py
+++ b/common.py
@@ -1,6 +1,7 @@
 """Misc common utilities."""
 import base64
 from datetime import timedelta
+import functools
 import logging
 from pathlib import Path
 import re
@@ -9,6 +10,7 @@ import urllib.parse
 from urllib.parse import urljoin, urlparse
 
 import cachetools
+from cachetools.keys import hashkey
 from Crypto.Util import number
 from flask import abort, g, has_request_context, make_response, request
 from google.cloud.error_reporting.util import build_flask_context
@@ -413,3 +415,29 @@ def memcache_key(key):
     pymemcache Client's allow_unicode_keys constructor kwarg.
     """
     return key[:MEMCACHE_KEY_MAX_LEN].replace(' ', '%20').encode()
+
+
+def memcache_memoize(expire=None):
+    """Memoize function decorator that stores the cached value in memcache.
+
+    Only caches non-null/empty values.
+
+    Args:
+      expire (int): optional, expiration in seconds
+    """
+    def decorator(fn):
+        @functools.wraps(fn)
+        def wrapped(*args, **kwargs):
+            key = memcache_key(f'{fn.__name__}-{str(hashkey(*args, **kwargs))}')
+            if val := memcache.get(key):
+                logger.debug(f'cache hit {key}')
+                return val
+
+            logger.debug(f'cache miss {key}')
+            val = fn(*args, **kwargs)
+            memcache.set(key, val)
+            return val
+
+        return wrapped
+
+    return decorator
diff --git a/config.py b/config.py
index 44bf8fb..3a15778 100644
--- a/config.py
+++ b/config.py
@@ -29,7 +29,7 @@ else:
     if logging_client := getattr(appengine_config, 'logging_client'):
         logging_client.setup_logging(log_level=logging.INFO)
 
-    for logger in ('oauth_dropins.webutil.webmention', 'lexrpc'):
+    for logger in ('common', 'oauth_dropins.webutil.webmention', 'lexrpc'):
         logging.getLogger(logger).setLevel(logging.DEBUG)
 
 os.environ.setdefault('APPVIEW_HOST', 'api.bsky.local')
diff --git a/models.py b/models.py
index eec1416..38ce86c 100644
--- a/models.py
+++ b/models.py
@@ -30,6 +30,7 @@ from common import (
     base64_to_long,
     DOMAIN_RE,
     long_to_base64,
+    memcache_memoize,
     OLD_ACCOUNT_AGE,
     remove,
     report_error,
@@ -1563,6 +1564,7 @@ def get_original(copy_id, keys_only=None):
         return got[0]
 
 
+@memcache_memoize(expire=60 * 60 * 24)  # 1d
 def get_originals(copy_ids, keys_only=None):
     """Fetches users (across all protocols) for a given set of copies.
 
@@ -1577,7 +1579,7 @@ def get_originals(copy_ids, keys_only=None):
     """
     assert copy_ids
 
-    classes = set(cls for cls in PROTOCOLS.values() if cls)
+    classes = set(cls for cls in PROTOCOLS.values() if cls and cls.LABEL != 'ui')
     classes.add(Object)
 
     return list(itertools.chain(*(
diff --git a/tests/test_models.py b/tests/test_models.py
index 1801cbb..f255998 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -1102,6 +1102,13 @@ class ObjectTest(TestCase):
         user = self.make_user('other:user', cls=OtherFake,
                               copies=[Target(uri='fake:bar', protocol='fake')])
 
+        memcache_key = "get_originals-(['other:foo',%20'fake:bar',%20'baz'],)"
+        self.assertIsNone(common.memcache.get(memcache_key))
+
+        self.assert_entities_equal(
+            [obj, user], models.get_originals(['other:foo', 'fake:bar', 'baz']))
+
+        self.assertIsNotNone(common.memcache.get(memcache_key))
         self.assert_entities_equal(
             [obj, user], models.get_originals(['other:foo', 'fake:bar', 'baz']))