diff --git a/hypopub.py b/hypopub.py
index 222d6e7..c61874b 100644
--- a/hypopub.py
+++ b/hypopub.py
@@ -44,7 +44,7 @@ def send_micropub(entry: atoma.atom.AtomEntry):
             "content":[{
                 "html": entry.content.value
             }],
-            "category": annotation['tags'] + ['hypothes.is'],
+            "category": annotation['tags'] + ['hypothesis'],
             "in-reply-to": [annotation['target'][0]['source']],
             "hypothesis-link": [json_link]
       }