diff --git a/app/api/inngest/functions/index_post_mention.ts b/app/api/inngest/functions/index_post_mention.ts
--- a/app/api/inngest/functions/index_post_mention.ts
+++ b/app/api/inngest/functions/index_post_mention.ts
@@ -46,12 +46,12 @@
     ).toString();
 
     await step.run("index-bsky-post", async () => {
-      await supabaseServerClient.from("bsky_posts").insert({
+      await supabaseServerClient.from("bsky_posts").upsert({
         uri: bsky_post.uri,
         cid: bsky_post.cid,
         post_view: bsky_post as Json,
       });
-      await supabaseServerClient.from("document_mentions_in_bsky").insert({
+      await supabaseServerClient.from("document_mentions_in_bsky").upsert({
         uri: bsky_post.uri,
         document: documentUri,
         link: event.data.document_link,
@@ -61,17 +61,29 @@
     await step.run("create-notification", async () => {
       // Only create notification if the quote is from someone other than the author
       if (bsky_post.author.did !== pub.identity_did) {
-        const notification: Notification = {
-          id: v7(),
-          recipient: pub.identity_did,
-          data: {
-            type: "quote",
-            bsky_post_uri: bsky_post.uri,
-            document_uri: documentUri,
-          },
-        };
-        await supabaseServerClient.from("notifications").insert(notification);
-        await pingIdentityToUpdateNotification(pub.identity_did);
+        // Check if a notification already exists for this post and recipient
+        const { data: existingNotification } = await supabaseServerClient
+          .from("notifications")
+          .select("id")
+          .eq("recipient", pub.identity_did)
+          .eq("data->>type", "quote")
+          .eq("data->>bsky_post_uri", bsky_post.uri)
+          .eq("data->>document_uri", documentUri)
+          .single();
+
+        if (!existingNotification) {
+          const notification: Notification = {
+            id: v7(),
+            recipient: pub.identity_did,
+            data: {
+              type: "quote",
+              bsky_post_uri: bsky_post.uri,
+              document_uri: documentUri,
+            },
+          };
+          await supabaseServerClient.from("notifications").insert(notification);
+          await pingIdentityToUpdateNotification(pub.identity_did);
+        }
       }
     });
   },