diff --git a/packages/system/src/event-ext.ts b/packages/system/src/event-ext.ts
index 739c69796..f2727147e 100644
--- a/packages/system/src/event-ext.ts
+++ b/packages/system/src/event-ext.ts
@@ -4,6 +4,7 @@ import { getPublicKey, sha256, unixNow } from "@snort/shared";
 
 import { EventKind, HexKey, NostrEvent, NotSignedNostrEvent } from ".";
 import { minePow } from "./pow-util";
+import { findTag } from "./utils";
 
 export interface Tag {
   key: string;
@@ -19,6 +20,12 @@ export interface Thread {
   pubKeys: Array<HexKey>;
 }
 
+export const enum EventType {
+  Regular,
+  Replaceable,
+  ParameterizedReplaceable,
+}
+
 export abstract class EventExt {
   /**
    * Get the pub key of the creator of this event NIP-26
@@ -149,4 +156,25 @@ export abstract class EventExt {
     e.pubkey ??= "";
     e.sig ??= "";
   }
+
+  static getType(kind: number) {
+    const legacyReplaceable = [0, 3, 41];
+    if (kind >= 30_000 && kind < 40_000) {
+      return EventType.ParameterizedReplaceable;
+    } else if (kind >= 10_000 && kind < 20_000) {
+      return EventType.Replaceable;
+    } else if (legacyReplaceable.includes(kind)) {
+      return EventType.Replaceable;
+    } else {
+      return EventType.Regular;
+    }
+  }
+
+  static isValid(ev: NostrEvent) {
+    const type = EventExt.getType(ev.kind);
+    if (type === EventType.ParameterizedReplaceable) {
+      if (!findTag(ev, "d")) return false;
+    }
+    return true;
+  }
 }
diff --git a/packages/system/src/nostr-system.ts b/packages/system/src/nostr-system.ts
index 9a5719d34..283338225 100644
--- a/packages/system/src/nostr-system.ts
+++ b/packages/system/src/nostr-system.ts
@@ -18,6 +18,7 @@ import {
   RelayMetricCache,
   UsersRelays,
   SnortSystemDb,
+  EventExt,
 } from ".";
 import { EventsCache } from "./cache/events";
 import { RelayCache } from "./gossip-model";
@@ -178,6 +179,8 @@ export class NostrSystem extends ExternalStore<SystemSnapshot> implements System
   }
 
   #onEvent(sub: string, ev: TaggedNostrEvent) {
+    if (!EventExt.isValid(ev)) return;
+
     for (const [, v] of this.Queries) {
       v.handleEvent(sub, ev);
     }
diff --git a/packages/system/src/note-collection.ts b/packages/system/src/note-collection.ts
index 54009ddff..642039deb 100644
--- a/packages/system/src/note-collection.ts
+++ b/packages/system/src/note-collection.ts
@@ -1,5 +1,5 @@
 import { appendDedupe } from "@snort/shared";
-import { TaggedNostrEvent, u256 } from ".";
+import { EventExt, EventType, TaggedNostrEvent, u256 } from ".";
 import { findTag } from "./utils";
 
 export interface StoreSnapshot<TSnapshot> {
@@ -268,18 +268,13 @@ export class ReplaceableNoteStore extends HookedNoteStore<Readonly<TaggedNostrEv
 export class NoteCollection extends KeyedReplaceableNoteStore {
   constructor() {
     super(e => {
-      const legacyReplaceable = [0, 3, 41];
-      if (e.kind >= 30_000 && e.kind < 40_000) {
-        return `${e.kind}:${e.pubkey}:${findTag(e, "d")}`; // Parameterized replaceable
-      } else if (e.kind >= 10_000 && e.kind < 20_000) {
-        return `${e.kind}:${e.pubkey}`; // Replaceable event
-      } else if (legacyReplaceable.includes(e.kind)) {
-        return `${e.kind}:${e.pubkey}`; // Replaceable event
-      } else {
-        // Regular event
-        // ephemeral events are like regular events
-        // unknown kind
-        return e.id;
+      switch (EventExt.getType(e.kind)) {
+        case EventType.ParameterizedReplaceable:
+          return `${e.kind}:${e.pubkey}:${findTag(e, "d")}`;
+        case EventType.Replaceable:
+          return `${e.kind}:${e.pubkey}`;
+        default:
+          return e.id;
       }
     });
   }