RTFM

shiftregister/app/models.py

@@ -103,7 +103,7 @@ class Message(models.Model):
 
 
 def gen_token():
-    return secrets.token_urlsafe(20)
+    return secrets.token_urlsafe(15) # returns 15 bytes Base64-encoded (times 1.333...) = 20 characters
 
 
 class LoginToken(models.Model):