diff --git a/app/models/_constants.py b/app/models/_constants.py
index ca26638..180c14a 100644
--- a/app/models/_constants.py
+++ b/app/models/_constants.py
@@ -52,6 +52,12 @@ PLATFORM_CODES = {
     'Epic': 'epic',
 }
 
+PLATFORM_DEFAULTS = {
+    'Apex Legends': 'pc',
+    'Rainbow Six Siege': 'ubi',
+    'Rocket League': 'epic'
+}
+
 TRN_URLS = {
     'Valorant': 'https://tracker.gg/valorant/profile/riot/{username}',
     'League of Legends': 'https://tracker.gg/lol/profile/{username}',
diff --git a/app/models/user_gamertag.py b/app/models/user_gamertag.py
index aa85eec..ed8b729 100644
--- a/app/models/user_gamertag.py
+++ b/app/models/user_gamertag.py
@@ -1,6 +1,6 @@
 """Store gamertag per game for each user."""
 from app.extensions import db
-from app.models._constants import TRN_URLS, PLATFORM_CODES
+from app.models._constants import TRN_URLS, PLATFORM_CODES, PLATFORM_DEFAULTS
 from urllib.parse import quote
 
 
@@ -24,17 +24,21 @@ class UserGamertag(db.Model):
             return None
         url = TRN_URLS[self.game]
         encoded_gamertag = quote(self.gamertag, safe='')
+        # Resolve platform: use user's selection, or fall back to game default
+        platform = self.platform
+        if not platform:
+            platform = PLATFORM_DEFAULTS.get(self.game, '')
         if '{platform_code}' in url and '{username}' in url:
             platform_code = PLATFORM_CODES.get(
-                self.platform,
-                self.platform.lower().replace(' ', '-') if self.platform else '',
+                platform,
+                platform.lower().replace(' ', '-') if platform else '',
             )
             return url.format(platform_code=platform_code, username=encoded_gamertag)
         elif '{platform}' in url and '{username}' in url:
             return url.format(
-                platform=self.platform.lower().replace(' ', '-'),
+                platform=platform.lower().replace(' ', '-') if platform else '',
                 username=encoded_gamertag,
             )
         elif '{username}' in url:
             return url.format(username=encoded_gamertag)
-        return url
\ No newline at end of file
+        return url