diff --git a/js/app.js b/js/app.js
index 3954d30c..8c3fea39 100644
--- a/js/app.js
+++ b/js/app.js
@@ -3197,8 +3197,9 @@ class Application {
     }
 
     let relaySummary = null;
+    let publishResult = null;
     try {
-      const publishResult = await this.nostrService.publishVideoNote(
+      publishResult = await this.nostrService.publishVideoNote(
         publishPayload,
         this.pubkey,
       );
@@ -3219,10 +3220,31 @@ class Application {
       this.uploadModal.close();
     }
 
+    // Optimistically insert the just-published note into the shared cache so it
+    // appears in the feed instantly, before the relays echo it back. Obeys the
+    // same dedupe/active-key rules as live ingestion, so a later relay copy
+    // won't duplicate it (see #20/#21).
+    try {
+      if (publishResult?.legacy) {
+        this.nostrService.ingestLocalVideoEvent(publishResult.legacy);
+      }
+    } catch (error) {
+      devLogger.warn(
+        "[Application] Optimistic feed insert after publishing failed:",
+        error,
+      );
+    }
+
     let loadVideosError = null;
 
     try {
-      await this.loadVideos();
+      // Refresh whichever feed is active (For You / Explore / Recent) plus the
+      // subscription and channel grids — not just the main recent feed — and
+      // force a render so the newly injected video is shown.
+      await this.refreshAllVideoGrids({
+        reason: "video-published",
+        forceMainReload: true,
+      });
     } catch (error) {
       loadVideosError = error;
       devLogger.error(
diff --git a/js/nostr/client.js b/js/nostr/client.js
index 38d8993c..e7fa1fd2 100644
--- a/js/nostr/client.js
+++ b/js/nostr/client.js
@@ -4306,6 +4306,62 @@ export class NostrClient {
     );
   }
 
+  // Optimistically add a just-published video event to the local caches so it
+  // shows in the feed immediately, without waiting for it to propagate back
+  // from the relays. Mirrors the per-event ingestion the live subscription and
+  // fetchVideosByAuthors use (convert → root created_at → tombstone guard →
+  // allEvents/activeMap), so it obeys the same dedupe/active-key rules — a later
+  // relay copy of the same event (same created_at) won't displace it, and an
+  // older revision can't overwrite a newer active entry. Returns the ingested
+  // video, or null if the event isn't a usable video note.
+  ingestLocalVideoEvent(rawEvent) {
+    if (!rawEvent || typeof rawEvent !== "object" || !rawEvent.id) {
+      return null;
+    }
+
+    let video;
+    try {
+      video = convertEventToVideo(rawEvent);
+    } catch (error) {
+      devLogger.warn(
+        "[nostr] Failed to convert published event for optimistic feed insert:",
+        error,
+      );
+      return null;
+    }
+    if (!video || video.invalid) {
+      return null;
+    }
+
+    this.applyRootCreatedAt(video);
+    if (this.rawEvents && typeof this.rawEvents.set === "function") {
+      this.rawEvents.set(rawEvent.id, rawEvent);
+    }
+
+    const activeKey = getActiveKey(video);
+    if (video.deleted) {
+      this.recordTombstone(activeKey, video.created_at);
+      return video;
+    }
+
+    this.applyTombstoneGuard(video);
+    if (video.deleted) {
+      // A tombstone guard flipped it to deleted — don't surface it.
+      return video;
+    }
+
+    this.allEvents.set(rawEvent.id, video);
+    this.dirtyEventIds.add(rawEvent.id);
+
+    const existing = this.activeMap.get(activeKey);
+    if (!existing || video.created_at > existing.created_at) {
+      this.activeMap.set(activeKey, video);
+      this.applyRootCreatedAt(video);
+    }
+
+    return video;
+  }
+
   handleEvent(event) {
     if (!event || typeof event !== "object") return;
 
diff --git a/js/services/nostrService.js b/js/services/nostrService.js
index 639f2713..203d915f 100644
--- a/js/services/nostrService.js
+++ b/js/services/nostrService.js
@@ -1575,6 +1575,24 @@ export class NostrService {
     return this.filterVideos(all, options);
   }
 
+  // Optimistically insert a just-published video into the shared client caches
+  // so the feed can render it before it round-trips through the relays. Keeps
+  // the author index in sync so channel/subscription grids reflect it too.
+  ingestLocalVideoEvent(rawEvent) {
+    if (
+      !this.nostrClient ||
+      typeof this.nostrClient.ingestLocalVideoEvent !== "function"
+    ) {
+      return null;
+    }
+    const video = this.nostrClient.ingestLocalVideoEvent(rawEvent);
+    if (video && !video.deleted && !video.invalid) {
+      this.markAuthorIndexDirty();
+      this.emit("videos:updated", { videos: null, reason: "local-publish" });
+    }
+    return video;
+  }
+
   getActiveVideosByAuthors(authors = [], options = {}) {
     const candidates = ensureSet(authors);
     const normalizedAuthors = new Set();
diff --git a/tests/optimistic-feed-insert.test.mjs b/tests/optimistic-feed-insert.test.mjs
new file mode 100644
index 00000000..fe2896bc
--- /dev/null
+++ b/tests/optimistic-feed-insert.test.mjs
@@ -0,0 +1,112 @@
+// Optimistic feed insert after publishing (#46): a just-published video is
+// added to the client's active-video cache immediately so it shows in the feed
+// without waiting for the relays to echo it back — while still obeying the same
+// dedupe / active-key rules as live ingestion, so a relay copy of the same
+// event can't duplicate it and an older revision can't overwrite a newer one.
+//
+// test_integrity_note:
+//   change_type: ["new_tests"]
+//   scenarios:
+//     - id: SCN-optimistic-feed-insert
+//       given: "a freshly signed video event"
+//       when: "ingestLocalVideoEvent is called with it"
+//       then: "getActiveVideos includes it exactly once, newest-revision-wins"
+//   observable_outcomes:
+//     - "getActiveVideos() surfaces the ingested video"
+//     - "re-ingesting the same event does not create a duplicate active entry"
+//     - "an older revision of the same root does not replace a newer active one"
+//     - "an invalid event returns null and inserts nothing"
+//   determinism_controls:
+//     - "in-memory NostrClient + localStorage polyfill; explicit created_at values"
+//   anti_cheat_rationale:
+//     prevents: ["hard-coded return value", "over-mocking internal logic"]
+//   relaxation:
+//     did_relax_any_assertion: false
+
+import "./test-helpers/setup-localstorage.mjs";
+import test from "node:test";
+import { strict as assert } from "node:assert";
+import { NostrClient } from "../js/nostr/client.js";
+
+const PUB = "f".repeat(64);
+
+function videoEvent({ id, root, title, createdAt }) {
+  return {
+    id,
+    pubkey: PUB,
+    kind: 30078,
+    created_at: createdAt,
+    content: JSON.stringify({
+      version: 3,
+      title,
+      url: "https://cdn.example/v.mp4",
+      videoRootId: root,
+    }),
+    tags: [["d", root]],
+  };
+}
+
+test("a published event is surfaced in the active feed immediately", () => {
+  const client = new NostrClient();
+  const video = client.ingestLocalVideoEvent(
+    videoEvent({ id: "evt-1", root: "root-1", title: "Hello", createdAt: 1000 }),
+  );
+
+  assert.ok(video, "returns the ingested video");
+  const active = client.getActiveVideos();
+  assert.equal(active.length, 1);
+  assert.equal(active[0].id, "evt-1");
+  assert.equal(active[0].title, "Hello");
+});
+
+test("re-ingesting the same event does not duplicate it in the feed", () => {
+  const client = new NostrClient();
+  const evt = videoEvent({ id: "evt-1", root: "root-1", title: "Hello", createdAt: 1000 });
+  client.ingestLocalVideoEvent(evt);
+  client.ingestLocalVideoEvent(evt);
+
+  assert.equal(client.getActiveVideos().length, 1, "same event stays a single active entry");
+});
+
+test("a newer revision of the same root replaces the active entry", () => {
+  const client = new NostrClient();
+  client.ingestLocalVideoEvent(
+    videoEvent({ id: "evt-old", root: "root-1", title: "Old", createdAt: 1000 }),
+  );
+  client.ingestLocalVideoEvent(
+    videoEvent({ id: "evt-new", root: "root-1", title: "New", createdAt: 2000 }),
+  );
+
+  const active = client.getActiveVideos();
+  assert.equal(active.length, 1, "one active entry per root");
+  assert.equal(active[0].title, "New", "newest revision wins");
+});
+
+test("an older revision does NOT overwrite a newer active entry", () => {
+  const client = new NostrClient();
+  client.ingestLocalVideoEvent(
+    videoEvent({ id: "evt-new", root: "root-1", title: "New", createdAt: 2000 }),
+  );
+  // A late-arriving older copy (e.g. a stale relay echo) must not clobber it.
+  client.ingestLocalVideoEvent(
+    videoEvent({ id: "evt-old", root: "root-1", title: "Old", createdAt: 1000 }),
+  );
+
+  const active = client.getActiveVideos();
+  assert.equal(active.length, 1);
+  assert.equal(active[0].title, "New", "older revision must not displace the newer active entry");
+});
+
+test("an invalid event returns null and inserts nothing", () => {
+  const client = new NostrClient();
+  const result = client.ingestLocalVideoEvent({ id: "bad", content: "not-json", tags: [] });
+  assert.equal(result, null);
+  assert.equal(client.getActiveVideos().length, 0);
+});
+
+test("a null/garbage argument is handled without throwing", () => {
+  const client = new NostrClient();
+  assert.equal(client.ingestLocalVideoEvent(null), null);
+  assert.equal(client.ingestLocalVideoEvent({}), null);
+  assert.equal(client.getActiveVideos().length, 0);
+});
diff --git a/todo/TODO_2026-06-20_pre-launch.md b/todo/TODO_2026-06-20_pre-launch.md
index 0dc12b4f..e2cb65dc 100644
--- a/todo/TODO_2026-06-20_pre-launch.md
+++ b/todo/TODO_2026-06-20_pre-launch.md
@@ -579,12 +579,21 @@ toward freshness and looked identical. Gave each a structural identity:
       Rank by usage count; clicking a chip adds it to the new video's tags.
 
 ### 46. Feed auto-refreshes after posting a video (UX)
-- [ ] After a video note is published, **automatically refresh the feed** so the new
-      video appears without a manual page reload. Hook the post-publish success (upload
-      modal `upload:submit` / `publishVideoNote` completion) to
-      `refreshAllVideoGrids`/`onVideosShouldRefresh` (optimistically inject the just-
-      published event so it shows instantly). Mind the feed-identity + dedupe paths (#20/
-      #21) so the injected event isn't dropped or duplicated.
+- [x] **DONE 2026-06-30.** `publishVideoNote` now (1) **optimistically injects** the
+      just-published legacy event into the shared client cache via a new
+      `nostrClient.ingestLocalVideoEvent(rawEvent)` (+ thin `nostrService` wrapper), so the
+      new video shows in the feed **instantly**, before the relays echo it back; and (2)
+      refreshes via the canonical `refreshAllVideoGrids({ reason: "video-published",
+      forceMainReload: true })` instead of a bare `loadVideos()` — so it refreshes
+      **whichever feed is active** (For You / Explore / Recent) plus the subscription and
+      channel grids, and forces a render (bypassing the load cooldown) so the injected
+      video is actually shown. `ingestLocalVideoEvent` mirrors live ingestion (convert →
+      root created_at → tombstone guard → allEvents/activeMap), so it obeys the same
+      dedupe/active-key rules (#20/#21): a later relay copy of the same event (same
+      `created_at`) won't duplicate it, and an older revision can't overwrite a newer
+      active entry. Tests: `tests/optimistic-feed-insert.test.mjs` (6 — surfaced instantly,
+      no-duplicate on re-ingest, newer-wins, older-doesn't-clobber, invalid→null, garbage
+      handled).
 
 ### 47. "Most Zapped" sidebar tab (trending-by-zaps)
 - [ ] Add a **Most Zapped** sidebar tab: like Trending (#27, view-count) but ranked by