diff --git a/scripts/perf/diagnose-feed.mjs b/scripts/perf/diagnose-feed.mjs
new file mode 100644
index 00000000..cb00f74c
--- /dev/null
+++ b/scripts/perf/diagnose-feed.mjs
@@ -0,0 +1,44 @@
+import { chromium } from "playwright";
+
+const URL = process.argv[2] || "http://localhost:3000/";
+const WAIT_MS = Number(process.env.WAIT_MS || 20000);
+
+const browser = await chromium.launch({ headless: true });
+const page = await browser.newPage({ viewport: { width: 1280, height: 900 } });
+
+const logs = [];
+page.on("console", (m) => logs.push(`[${m.type()}] ${m.text()}`.slice(0, 300)));
+page.on("pageerror", (e) => logs.push(`[pageerror] ${String(e).split("\n")[0]}`));
+
+await page.goto(URL, { waitUntil: "domcontentloaded" });
+await page.waitForTimeout(WAIT_MS);
+
+const state = await page.evaluate(async () => {
+  const out = {};
+  try {
+    const t = window.__bitvidTest__;
+    out.harness = !!t;
+    if (t && typeof t.getAppState === "function") {
+      out.appState = await t.getAppState();
+    }
+  } catch (e) {
+    out.harnessError = String(e).split("\n")[0];
+  }
+  const list = document.querySelector('[data-testid="video-list"]');
+  out.videoListFound = !!list;
+  out.videoListChildCount = list ? list.children.length : null;
+  out.videoListText = list ? (list.textContent || "").trim().slice(0, 200) : null;
+  out.cardsByDataVideoId = document.querySelectorAll("[data-video-id]").length;
+  // any visible error/lockdown banners
+  out.bodyTextSample = (document.body.textContent || "").replace(/\s+/g, " ").trim().slice(0, 400);
+  return out;
+});
+
+console.log("\n===== FEED DIAGNOSIS =====");
+console.log(JSON.stringify(state, null, 2));
+console.log("\n===== CONSOLE (errors/warnings first 40) =====");
+for (const l of logs.filter((l) => /error|warn|fail|lockdown|relay|reject/i.test(l)).slice(0, 40)) {
+  console.log(l);
+}
+console.log(`\n(total console lines: ${logs.length})`);
+await browser.close();
diff --git a/scripts/perf/profile-live.mjs b/scripts/perf/profile-live.mjs
new file mode 100644
index 00000000..e7e4b269
--- /dev/null
+++ b/scripts/perf/profile-live.mjs
@@ -0,0 +1,138 @@
+// Standalone live profiler for the running bitvid dev server.
+// Drives the real app in Chromium, captures a CPU profile (CDP Profiler) and a
+// long-task report during cold load + interaction, then prints the hottest
+// functions by self-time and the worst long tasks.
+//
+// Usage: node scripts/perf/profile-live.mjs [url]
+//   default url: http://localhost:3000/
+
+import { chromium } from "playwright";
+
+const URL = process.argv[2] || "http://localhost:3000/";
+const SETTLE_MS = Number(process.env.SETTLE_MS || 18000);
+
+function fmt(ms) {
+  return `${ms.toFixed(0)}ms`;
+}
+
+async function main() {
+  const browser = await chromium.launch({ headless: true });
+  const context = await browser.newContext({ viewport: { width: 1280, height: 900 } });
+  const page = await context.newPage();
+
+  // Long-task observer installed before any app code runs.
+  await page.addInitScript(() => {
+    window.__longtasks__ = [];
+    try {
+      const obs = new PerformanceObserver((list) => {
+        for (const entry of list.getEntries()) {
+          window.__longtasks__.push({
+            start: entry.startTime,
+            duration: entry.duration,
+            name: entry.name,
+            attribution: (entry.attribution || []).map((a) => ({
+              name: a.name,
+              containerType: a.containerType,
+              containerName: a.containerName,
+              containerSrc: a.containerSrc,
+            })),
+          });
+        }
+      });
+      obs.observe({ entryTypes: ["longtask"] });
+    } catch (e) {
+      // longtask not supported
+    }
+    window.__marks__ = {};
+    window.__t0__ = performance.now();
+  });
+
+  const cdp = await context.newCDPSession(page);
+  await cdp.send("Profiler.enable");
+  await cdp.send("Profiler.setSamplingInterval", { interval: 100 }); // 100us
+  await cdp.send("Profiler.start");
+
+  const navStart = Date.now();
+  await page.goto(URL, { waitUntil: "domcontentloaded" });
+
+  // Time-to-first-video-card.
+  let firstCardMs = null;
+  try {
+    await page.waitForSelector('[data-testid="video-list"] a, [data-testid="video-list"] [data-video-id], [data-testid="video-list"] article', { timeout: SETTLE_MS });
+    firstCardMs = Date.now() - navStart;
+  } catch (e) {
+    firstCardMs = null;
+  }
+
+  // Let the feed settle / stream in.
+  await page.waitForTimeout(SETTLE_MS);
+
+  // Interaction: scroll the feed, then try a tab/nav switch to surface jank.
+  await page.evaluate(async () => {
+    window.__marks__.scrollStart = performance.now();
+    for (let i = 0; i < 8; i++) {
+      window.scrollBy(0, 800);
+      await new Promise((r) => setTimeout(r, 120));
+    }
+    window.__marks__.scrollEnd = performance.now();
+  });
+
+  // Try clicking nav links (subscriptions / explore / home) to switch views.
+  const navClicks = [];
+  for (const sel of ["#subscriptionsLink", 'a[href="#view=explore"]', 'a[href="#view=subscriptions"]', 'a[href="#view=home"]']) {
+    const el = await page.$(sel);
+    if (el) {
+      const t = Date.now();
+      try {
+        await el.click({ timeout: 2000 });
+        await page.waitForTimeout(1500);
+        navClicks.push({ sel, ms: Date.now() - t });
+      } catch (e) {
+        navClicks.push({ sel, error: String(e).split("\n")[0] });
+      }
+    }
+  }
+
+  const { profile } = await cdp.send("Profiler.stop");
+
+  // Aggregate self-time by function (node hitCount * sampling interval).
+  const intervalMs = 0.1; // 100us
+  const byFn = new Map();
+  const nodeById = new Map();
+  for (const node of profile.nodes) nodeById.set(node.id, node);
+  for (const node of profile.nodes) {
+    const cf = node.callFrame;
+    const key = `${cf.functionName || "(anonymous)"} @ ${(cf.url || "").split("/").slice(-1)[0]}:${cf.lineNumber + 1}`;
+    const self = (node.hitCount || 0) * intervalMs;
+    byFn.set(key, (byFn.get(key) || 0) + self);
+  }
+  const topFns = [...byFn.entries()].sort((a, b) => b[1] - a[1]).slice(0, 25);
+
+  const longtasks = await page.evaluate(() => window.__longtasks__ || []);
+  const totalLongtaskMs = longtasks.reduce((s, t) => s + t.duration, 0);
+  const worst = [...longtasks].sort((a, b) => b.duration - a.duration).slice(0, 15);
+
+  console.log("\n================ LIVE PROFILE ================");
+  console.log(`URL: ${URL}`);
+  console.log(`Time-to-first-video-card: ${firstCardMs === null ? "NEVER (timed out)" : fmt(firstCardMs)}`);
+  console.log(`Nav switch timings: ${JSON.stringify(navClicks)}`);
+  console.log(`\nLong tasks: count=${longtasks.length}, total=${fmt(totalLongtaskMs)}`);
+  console.log("Worst long tasks (duration | attribution):");
+  for (const t of worst) {
+    const attr = (t.attribution[0] && (t.attribution[0].containerName || t.attribution[0].name)) || t.name;
+    console.log(`  ${fmt(t.duration).padStart(7)}  @ ${fmt(t.start)}  ${attr}`);
+  }
+
+  console.log(`\nTop functions by self-time (CPU profile):`);
+  for (const [fn, ms] of topFns) {
+    console.log(`  ${fmt(ms).padStart(8)}  ${fn}`);
+  }
+  console.log("=============================================\n");
+
+  await browser.close();
+}
+
+main().catch((e) => {
+  console.error("profiler failed:", e);
+  process.exit(1);
+});
diff --git a/scripts/perf/profile-seeded.mjs b/scripts/perf/profile-seeded.mjs
new file mode 100644
index 00000000..f6cb1e16
--- /dev/null
+++ b/scripts/perf/profile-seeded.mjs
@@ -0,0 +1,222 @@
+// Seeded live profiler: drives the dist build at localhost:3000 in test mode
+// against an in-process mock relay seeded with a heavy video feed, then captures
+// a CPU profile + long-task report across: cold feed render, tab switches, and
+// profile-modal open. Reproduces CPU/DOM render jank without real-relay latency.
+//
+// Prereq: dev server running at http://localhost:3000 (npm start).
+// Usage: node scripts/perf/profile-seeded.mjs [videoCount]
+
+import { chromium } from "playwright";
+import { startRelay } from "../agent/simple-relay.mjs";
+import { finalizeEvent, getPublicKey, generateSecretKey } from "nostr-tools";
+
+const VIDEO_COUNT = Number(process.argv[2] || 400);
+const APP = "http://localhost:3000";
+const WS_PORT = 8951;
+const TEST_SK_HEX = "7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b7b";
+const TEST_SK = Uint8Array.from(Buffer.from(TEST_SK_HEX, "hex"));
+
+function makeVideoEvent(i, sk, pk, createdAt) {
+  const dTag = `seed-${i}-${Math.random().toString(36).slice(2, 8)}`;
+  const content = {
+    version: 3,
+    title: `Seeded Video ${i}`,
+    videoRootId: dTag,
+    mode: "dev",
+    isPrivate: false,
+    deleted: false,
+    url: `https://example.com/v${i}.mp4`,
+    description: `Perf seed video number ${i}`,
+  };
+  return finalizeEvent(
+    {
+      kind: 30078,
+      created_at: createdAt,
+      tags: [
+        ["d", dTag],
+        ["t", "video"],
+        ["title", `Seeded Video ${i}`],
+        ["url", `https://example.com/v${i}.mp4`],
+      ],
+      content: JSON.stringify(content),
+      pubkey: pk,
+    },
+    sk,
+  );
+}
+
+const fmt = (ms) => `${ms.toFixed(0)}ms`;
+
+async function main() {
+  // 1. Mock relay (in-process; seed directly).
+  const relay = startRelay(WS_PORT, { httpPort: false });
+
+  // A few distinct authors so the feed looks realistic.
+  const authors = [];
+  for (let a = 0; a < 6; a++) {
+    const sk = a === 0 ? TEST_SK : generateSecretKey();
+    authors.push({ sk, pk: getPublicKey(sk) });
+  }
+  const now = Math.floor(Date.now() / 1000);
+  for (let i = 0; i < VIDEO_COUNT; i++) {
+    const author = authors[i % authors.length];
+    relay.seedEvent(makeVideoEvent(i, author.sk, author.pk, now - i * 60));
+  }
+  console.log(`Seeded ${VIDEO_COUNT} videos on ws://127.0.0.1:${WS_PORT}`);
+
+  // 2. Browser + test mode.
+  const browser = await chromium.launch({ headless: true });
+  const page = await browser.newPage({ viewport: { width: 1280, height: 900 } });
+
+  const relayUrl = `ws://127.0.0.1:${WS_PORT}`;
+  await page.addInitScript((url) => {
+    localStorage.setItem("hasSeenDisclaimer", "true");
+    localStorage.setItem("__bitvidTestMode__", "1");
+    localStorage.setItem("__bitvidTestRelays__", JSON.stringify([url]));
+    window.__bitvidTestRelays__ = [url];
+    localStorage.setItem("bitvid_admin_whitelist_mode", "false");
+    // long-task observer
+    window.__lt__ = [];
+    try {
+      new PerformanceObserver((l) => {
+        for (const e of l.getEntries()) window.__lt__.push({ s: e.startTime, d: e.duration });
+      }).observe({ entryTypes: ["longtask"] });
+    } catch (e) {}
+    window.__mark = (name) => { (window.__marks ||= {})[name] = performance.now(); };
+  }, relayUrl);
+
+  const logs = [];
+  page.on("console", (m) => logs.push(`[${m.type()}] ${m.text()}`.slice(0, 240)));
+  page.on("pageerror", (e) => logs.push(`[pageerror] ${String(e).split("\n")[0]}`));
+
+  const cdp = await page.context().newCDPSession(page);
+  await cdp.send("Profiler.enable");
+  await cdp.send("Profiler.setSamplingInterval", { interval: 100 });
+
+  const testUrl = `${APP}/?__test__=1&__testRelays__=${encodeURIComponent(relayUrl)}`;
+  await page.goto(testUrl, { waitUntil: "domcontentloaded" });
+  await page.waitForFunction(() => typeof window.__bitvidTest__ === "object", { timeout: 20000 }).catch(() => {});
+  // Replicate the e2e fixture: explicitly activate the test relay, then reload so
+  // the app boots its feed subscription against the mock relay (not real relays).
+  await page.evaluate((url) => window.__bitvidTest__?.setTestRelays?.([url], { persist: false }), relayUrl).catch(() => {});
+  await page.goto(testUrl, { waitUntil: "domcontentloaded" });
+  await page.waitForFunction(() => typeof window.__bitvidTest__ === "object", { timeout: 20000 }).catch(() => {});
+  await page.evaluate((url) => window.__bitvidTest__?.setTestRelays?.([url], { persist: false }), relayUrl).catch(() => {});
+
+  await cdp.send("Profiler.start");
+  const tNav = Date.now();
+
+  // 3. Time-to-first-card + rendered count.
+  let firstCardMs = null;
+  try {
+    await page.waitForSelector("[data-video-id]", { timeout: 25000 });
+    firstCardMs = Date.now() - tNav;
+  } catch (e) {}
+  await page.waitForTimeout(4000);
+  const cardCount = await page.evaluate(() => document.querySelectorAll("[data-video-id]").length);
+
+  // 4. Scroll jank.
+  await page.evaluate(async () => {
+    window.__mark("scrollStart");
+    for (let i = 0; i < 12; i++) { window.scrollBy(0, 900); await new Promise(r => setTimeout(r, 100)); }
+    window.__mark("scrollEnd");
+  });
+
+  // 5. Tab switches (by visible text).
+  const tabTimings = {};
+  for (const label of ["Recently Added", "Explore", "For You"]) {
+    const t = Date.now();
+    try {
+      await page.getByText(label, { exact: true }).first().click({ timeout: 3000 });
+      await page.waitForTimeout(1800);
+      tabTimings[label] = Date.now() - t;
+    } catch (e) {
+      tabTimings[label] = `ERR ${String(e).split("\n")[0].slice(0, 60)}`;
+    }
+  }
+
+  // 6. Login + open profile modal (the reported hitch).
+  let loginOk = false;
+  try {
+    loginOk = await page.evaluate(async (sk) => {
+      if (window.__bitvidTest__?.loginWithNsec) {
+        await window.__bitvidTest__.loginWithNsec(sk);
+        return true;
+      }
+      return false;
+    }, TEST_SK_HEX);
+  } catch (e) {}
+  await page.waitForTimeout(2500);
+
+  let profileModalMs = null;
+  try {
+    const t = Date.now();
+    await page.click('[data-testid="profile-button"]', { timeout: 3000 });
+    await page.waitForTimeout(2500);
+    profileModalMs = Date.now() - t;
+  } catch (e) {}
+
+  const { profile } = await cdp.send("Profiler.stop");
+
+  // Aggregate CPU self-time by function.
+  const byFn = new Map();
+  for (const node of profile.nodes) {
+    const cf = node.callFrame;
+    const file = (cf.url || "").split("/").slice(-1)[0];
+    const key = `${cf.functionName || "(anonymous)"} @ ${file}:${cf.lineNumber + 1}`;
+    byFn.set(key, (byFn.get(key) || 0) + (node.hitCount || 0) * 0.1);
+  }
+  const topFns = [...byFn.entries()].sort((a, b) => b[1] - a[1]).slice(0, 30);
+
+  // Caller attribution: for crypto/vendor leaf frames, attribute self-time to the
+  // nearest ANCESTOR that lives in app /js/ code, so we learn WHO drives the cost.
+  const parentOf = new Map();
+  const nodeById2 = new Map();
+  for (const node of profile.nodes) {
+    nodeById2.set(node.id, node);
+    for (const c of node.children || []) parentOf.set(c, node.id);
+  }
+  const isVendor = (url) => !url || /node_modules|modular\.mjs|weierstrass\.mjs|nostr-tools|nostr\.bundle|base\.mjs|sha256|webtorrent|\.bundle\.min/.test(url);
+  const isAppJs = (url) => /\/js\//.test(url) && !isVendor(url);
+  const cryptoByCaller = new Map();
+  for (const node of profile.nodes) {
+    const cf = node.callFrame;
+    if (!/modular\.mjs|weierstrass\.mjs/.test(cf.url || "")) continue;
+    const self = (node.hitCount || 0) * 0.1;
+    if (self <= 0) continue;
+    // walk up to nearest app frame
+    let cur = node.id, hops = 0, appKey = "(no app ancestor)";
+    while (cur !== undefined && hops < 60) {
+      const n = nodeById2.get(cur);
+      const u = n?.callFrame?.url || "";
+      if (isAppJs(u)) { appKey = `${n.callFrame.functionName || "(anon)"} @ ${u.split("/").slice(-1)[0]}:${n.callFrame.lineNumber + 1}`; break; }
+      cur = parentOf.get(cur); hops++;
+    }
+    cryptoByCaller.set(appKey, (cryptoByCaller.get(appKey) || 0) + self);
+  }
+  const topCryptoCallers = [...cryptoByCaller.entries()].sort((a, b) => b[1] - a[1]).slice(0, 12);
+
+  const lt = await page.evaluate(() => window.__lt__ || []);
+  const ltTotal = lt.reduce((s, t) => s + t.d, 0);
+  const worst = [...lt].sort((a, b) => b.d - a.d).slice(0, 12);
+
+  console.log("\n================ SEEDED PROFILE ================");
+  console.log(`Seeded videos: ${VIDEO_COUNT} | harness login: ${loginOk}`);
+  console.log(`Time-to-first-card: ${firstCardMs === null ? "NEVER" : fmt(firstCardMs)} | cards rendered: ${cardCount}`);
+  console.log(`Tab switch timings: ${JSON.stringify(tabTimings)}`);
+  console.log(`Profile-modal open: ${profileModalMs === null ? "FAILED" : fmt(profileModalMs)}`);
+  console.log(`\nLong tasks: count=${lt.length} total=${fmt(ltTotal)}; worst: ${worst.map(t => fmt(t.d)).join(", ")}`);
+  console.log(`\nTop functions by self-time:`);
+  for (const [fn, ms] of topFns) console.log(`  ${fmt(ms).padStart(8)}  ${fn}`);
+  console.log(`\nsecp256k1 crypto attributed to nearest APP caller:`);
+  for (const [fn, ms] of topCryptoCallers) console.log(`  ${fmt(ms).padStart(8)}  ${fn}`);
+  const errs = logs.filter((l) => /error|warn|fail|reject/i.test(l)).slice(0, 12);
+  if (errs.length) { console.log(`\nConsole (errors/warnings):`); errs.forEach((l) => console.log("  " + l)); }
+  console.log("===============================================\n");
+
+  await browser.close();
+  if (typeof relay.close === "function") await relay.close();
+  process.exit(0);
+}
+
+main().catch((e) => { console.error("seeded profiler failed:", e); process.exit(1); });