diff --git a/fjerkroa_bot/ai_responder.py b/fjerkroa_bot/ai_responder.py
index 95f016b..5e22aa4 100644
--- a/fjerkroa_bot/ai_responder.py
+++ b/fjerkroa_bot/ai_responder.py
@@ -9,6 +9,7 @@ import pickle
 from pathlib import Path
 from io import BytesIO
 from pprint import pformat
+from functools import lru_cache
 from typing import Optional, List, Dict, Any, Tuple
 
 
@@ -18,6 +19,7 @@ def pp(*args, **kw):
     return pformat(*args, **kw)
 
 
+@lru_cache(maxsize=300)
 def parse_json(content: str) -> Dict:
     content = content.strip()
     try:
@@ -49,6 +51,10 @@ def parse_maybe_json(json_string):
     return str(parsed_json)
 
 
+def same_channel(item1: Dict[str, Any], item2: Dict[str, Any]) -> bool:
+    return parse_json(item1['content']).get('channel') == parse_json(item2['content']).get('channel')
+
+
 class AIMessageBase(object):
     def __init__(self) -> None:
         pass
@@ -215,11 +221,7 @@ class AIResponder(object):
             del self.history[0]
         else:
             current = self.history[index]
-
-            def same_channel(item: Dict[str, Any]) -> bool:
-                return parse_json(item['content']).get('channel') == parse_json(current['content']).get('channel')
-
-            count = sum(1 for item in self.history if same_channel(item))
+            count = sum(1 for item in self.history if same_channel(item, current))
             if count > self.config.get('history-per-channel', 3):
                 del self.history[index]
             else: