diff --git a/core/lib/rules.py b/core/lib/rules.py
index cb1b013..fa1b26e 100644
--- a/core/lib/rules.py
+++ b/core/lib/rules.py
@@ -20,6 +20,8 @@ log = logs.get_logger("rules")
 SECONDS_PER_UNIT = {"s": 1, "m": 60, "h": 3600, "d": 86400, "w": 604800}
 
 MAX_WINDOW = 2592000
+MAX_AMOUNT_NTFY = 10
+MAX_AMOUNT_WEBHOOK = 1000
 
 
 class RuleParseError(Exception):
@@ -426,6 +428,7 @@ class NotificationRuleData(object):
         interval = self.cleaned_data.get("interval")
         window = self.cleaned_data.get("window")
         amount = self.cleaned_data.get("amount")
+        service = self.cleaned_data.get("service")
 
         on_demand = interval == 0
         if on_demand and window is not None:
@@ -477,6 +480,23 @@ class NotificationRuleData(object):
                     "window",
                 )
 
+        if amount is not None:
+            if service == "ntfy":
+                if amount > MAX_AMOUNT_NTFY:
+                    raise RuleParseError(
+                        f"Amount cannot be larger than {MAX_AMOUNT_NTFY} for ntfy",
+                        "amount",
+                    )
+            else:
+                if amount > MAX_AMOUNT_WEBHOOK:
+                    raise RuleParseError(
+                        (
+                            f"Amount cannot be larger than {MAX_AMOUNT_WEBHOOK} for "
+                            f"{service}"
+                        ),
+                        "amount",
+                    )
+
     def validate_permissions(self):
         """
         Validate permissions for the source and index variables.