diff --git a/libs/features/mep/addons/event.js b/libs/features/mep/addons/event.js
index 1e1bcd9e2db..59fda6c29e8 100644
--- a/libs/features/mep/addons/event.js
+++ b/libs/features/mep/addons/event.js
@@ -1,49 +1,110 @@
-import { isSignedOut, getConfig, getMepEnablement, loadIms } from '../../../utils/utils.js';
-import { getCookie } from '../../../martech/helpers.js';
+import { isSignedOut, getConfig, getMepEnablement, loadIms, getCookie } from '../../../utils/utils.js';
+
+const defaultReturn = { isRegistered: false };
+
+// Persist only what personalization reads; never the RF authToken/userKey.
+const store = window.localStorage;
+const TTL_REGISTERED = 24 * 60 * 60 * 1000;
+const TTL_UNREGISTERED = 3 * 60 * 1000;
+const cacheKey = (eventCode, userId) => `mep-event:${eventCode}:${userId}`;
+
+// TODO(MWPW-199051): enable once VEAL confirms the redirect-cookie name/domain.
+// When enabling, clearRegisteredFlag must set domain= to match — a host-only
+// delete won't clear a .adobe.com cookie, leaving the flag stuck.
+const REDIRECT_INVALIDATION_ENABLED = false;
+const justRegistered = (eventCode) => REDIRECT_INVALIDATION_ENABLED
+  && getCookie(`feds_${eventCode}_registeredByRedirect`) === 'true';
+/* c8 ignore next 3 */
+const clearRegisteredFlag = (eventCode) => {
+  document.cookie = `feds_${eventCode}_registeredByRedirect=; Max-Age=0; path=/`;
+};
+
+function readCache(eventCode, userId) {
+  try {
+    const raw = store.getItem(cacheKey(eventCode, userId));
+    if (!raw) return null;
+    const { isRegistered, inPersonAttendee, exp } = JSON.parse(raw);
+    if (!exp || Date.now() > exp) return null;
+    return { isRegistered, inPersonAttendee };
+  } catch {
+    return null;
+  }
+}
+
+function writeCache(eventCode, userId, data) {
+  try {
+    const ttl = data.isRegistered ? TTL_REGISTERED : TTL_UNREGISTERED;
+    store.setItem(cacheKey(eventCode, userId), JSON.stringify({
+      isRegistered: !!data.isRegistered,
+      inPersonAttendee: !!data.inPersonAttendee,
+      exp: Date.now() + ttl,
+    }));
+  } catch {
+    // storage unavailable — non-fatal
+  }
+}
 
 async function getUserId() {
-  if (isSignedOut() && !getMepEnablement('signedIn')) return false;
-  if (getMepEnablement('userId') !== 'undefined') return getMepEnablement('userId');
-  /* c8 ignore next 3 */
-  await loadIms();
-  const { userId } = await window.adobeIMS.getProfile();
-  return userId;
+  const signedInEnable = getMepEnablement('signedIn') || getMepEnablement('signedin');
+  if (isSignedOut() && !signedInEnable) return false;
+  const userIdEnable = getMepEnablement('userId') || getMepEnablement('userid');
+  if (userIdEnable && userIdEnable !== 'undefined') return userIdEnable;
+  /* c8 ignore start */
+  try {
+    await loadIms();
+    const { userId } = await window.adobeIMS.getProfile();
+    return userId;
+  } catch {
+    return false;
+  }
+  /* c8 ignore stop */
 }
-async function fetchFromRainfocus(eventId) {
+
+async function fetchFromRainfocus(eventCode) {
   const userId = await getUserId();
-  if (!userId) return {};
+  if (!userId) return defaultReturn;
+
+  /* c8 ignore next 3 */
+  if (justRegistered(eventCode)) {
+    store.removeItem(cacheKey(eventCode, userId));
+    clearRegisteredFlag(eventCode);
+  } else {
+    const cached = readCache(eventCode, userId);
+    if (cached) return cached;
+  }
 
   const accessToken = window.adobeIMS.getAccessToken()?.token;
-  if (!accessToken) return {};
+  if (!accessToken) return defaultReturn;
 
   const domainSuffix = getConfig()?.env?.name === 'prod' ? '' : '.stage';
-  const url = `https://www${domainSuffix}.adobe.com/events/api/rf-auth-seq-generic/${eventId}?user_id=${encodeURIComponent(userId)}`;
+  const url = `https://www${domainSuffix}.adobe.com/events/api/rf-auth-seq-generic/${eventCode}?user_id=${encodeURIComponent(userId)}`;
   try {
     const response = await fetch(url, {
       method: 'GET',
       headers: { Authorization: `Bearer ${accessToken}` },
       credentials: 'same-origin',
     });
-    if (response.ok) return response.json();
+    if (response.ok) {
+      // RF returns {} (not { isRegistered: false }) when not registered.
+      const data = { isRegistered: false, ...(await response.json()) };
+      writeCache(eventCode, userId, data);
+      return data;
+    }
     window.lana?.log(`Unable to fetch from Rainfocus: ${response.statusText}`, {
       tags: 'mep-event',
       severity: 'error',
     });
-    return {};
+    return defaultReturn;
   } catch (e) {
     window.lana?.log(`Unable to fetch from Rainfocus: ${e.toString()}`, {
       tags: 'mep-event',
       severity: 'error',
     });
-    return {};
+    return defaultReturn;
   }
 }
-export default async function init(eventId) {
-  if (eventId === true) return eventId;
-
-  const consentCookieValue = getCookie('OptanonConsent');
-  if (consentCookieValue?.includes('C0002:0')) return false;
 
-  const eventDetails = await fetchFromRainfocus(eventId);
-  return eventDetails?.isRegistered === true;
+export default async function init(eventCode) {
+  if (eventCode === true) return { isRegistered: eventCode };
+  return fetchFromRainfocus(eventCode);
 }
diff --git a/libs/features/personalization/personalization.js b/libs/features/personalization/personalization.js
index 94a2bd5d6ac..af471cdf2f1 100644
--- a/libs/features/personalization/personalization.js
+++ b/libs/features/personalization/personalization.js
@@ -1093,7 +1093,7 @@ async function getPersonalizationVariant(
     if (userEntitlements?.includes(name)) return true;
     const { lob, event } = config.mep.promises;
     if (lob && lob === name.split('lob-')[1]?.toLowerCase()) return true;
-    if (name === 'registered' && event) return true;
+    if (name === 'registered' && event?.isRegistered) return true;
     return PERSONALIZATION_KEYS.includes(name) && PERSONALIZATION_TAGS[name]();
   };
 
diff --git a/libs/utils/utils.js b/libs/utils/utils.js
index fe7f90cb39c..94dc5d6bcbb 100644
--- a/libs/utils/utils.js
+++ b/libs/utils/utils.js
@@ -2119,7 +2119,7 @@ export function enablePersonalizationV2() {
 }
 
 export function loadMepAddons() {
-  const mepAddons = ['lob', 'event-id'];
+  const mepAddons = ['lob', 'event-code'];
   const promises = {};
   mepAddons.forEach((addon) => {
     const enablement = getMepEnablement(addon);
diff --git a/test/features/mep/addons/event.test.js b/test/features/mep/addons/event.test.js
index 357d4ad05f4..062e5acedd3 100644
--- a/test/features/mep/addons/event.test.js
+++ b/test/features/mep/addons/event.test.js
@@ -27,34 +27,36 @@ const setMetadata = (name, content) => {
 describe('event', () => {
   beforeEach(() => {
     document.head.innerHTML = '';
+    localStorage.clear();
     setMetadata('signedIn', 'on');
     setCookie('OptanonConsent', 'C0002:1');
     window.adobeIMS = { getAccessToken: () => ({ token: '1234567890' }) };
   });
+  afterEach(() => {
+    setCookie('feds_adobe-max-2025_registeredByRedirect', '; Max-Age=0');
+  });
   it('should return true when sending true into init', async () => {
     const event = await init(true);
-    expect(event).to.equal(true);
-  });
-  it('should return false when consent cookie is set to C0002:0', async () => {
-    setCookie('OptanonConsent', 'C0002:0');
-    const event = await init('adobe-max-2025');
-    expect(event).to.equal(false);
+    expect(event.isRegistered).to.equal(true);
   });
   it('should return false when the user is signed out', async () => {
     document.head.innerHTML = '';
     const event = await init('adobe-max-2025');
-    expect(event).to.equal(false);
+    expect(event.isRegistered).to.equal(false);
   });
-  it('should return false when userId is set to off', async () => {
-    setMetadata('userId', 'off');
+  it('should read enablements from lowercase DA metadata', async () => {
+    document.head.innerHTML = '';
+    setMetadata('signedin', 'on');
+    setMetadata('userid', '1234567890');
+    setFetchResponse({ ok: true, isRegistered: true });
     const event = await init('adobe-max-2025');
-    expect(event).to.equal(false);
+    expect(event.isRegistered).to.equal(true);
   });
   it('should return false when getAccessToken returns an empty object', async () => {
     setMetadata('userId', '1234567890');
     window.adobeIMS.getAccessToken = () => Promise.resolve({});
     const event = await init('adobe-max-2025');
-    expect(event).to.equal(false);
+    expect(event.isRegistered).to.equal(false);
   });
   it('should return false when api returns false', async () => {
     setMetadata('userId', '1234567890');
@@ -63,7 +65,7 @@ describe('event', () => {
       isRegistered: false,
     });
     const event = await init('adobe-max-2025');
-    expect(event).to.equal(false);
+    expect(event.isRegistered).to.equal(false);
   });
   it('should return true when api returns true', async () => {
     setMetadata('userId', '1234567890');
@@ -72,6 +74,32 @@ describe('event', () => {
       isRegistered: true,
     });
     const event = await init('adobe-max-2025');
-    expect(event).to.equal(true);
+    expect(event.isRegistered).to.equal(true);
+  });
+  it('should serve a cached result without re-calling the API', async () => {
+    setMetadata('userId', '1234567890');
+    setFetchResponse({ ok: true, isRegistered: true });
+    const first = await init('adobe-max-2025');
+    expect(first.isRegistered).to.equal(true);
+    // A cache hit must ignore a now-changed API response.
+    setFetchResponse({ ok: true, isRegistered: false });
+    const second = await init('adobe-max-2025');
+    expect(second.isRegistered).to.equal(true);
+  });
+  it('should normalize an empty API response to isRegistered false', async () => {
+    setMetadata('userId', '1234567890');
+    setFetchResponse({});
+    const event = await init('adobe-max-2025');
+    expect(event.isRegistered).to.equal(false);
+  });
+  // Un-skip when REDIRECT_INVALIDATION_ENABLED flips on (MWPW-199051).
+  it.skip('should bypass the cache when the registration-redirect cookie is set', async () => {
+    setMetadata('userId', '1234567890');
+    setFetchResponse({ ok: true, isRegistered: false });
+    await init('adobe-max-2025');
+    setCookie('feds_adobe-max-2025_registeredByRedirect', 'true');
+    setFetchResponse({ ok: true, isRegistered: true });
+    const event = await init('adobe-max-2025');
+    expect(event.isRegistered).to.equal(true);
   });
 });
diff --git a/test/utils/utils-mep.test.js b/test/utils/utils-mep.test.js
index 935fa1c0b6d..7abde7ac304 100644
--- a/test/utils/utils-mep.test.js
+++ b/test/utils/utils-mep.test.js
@@ -120,6 +120,16 @@ describe('MEP Utils', () => {
       console.log(promises);
       expect(promises.lob).to.be.a('promise');
     });
+    it('loads event from event-code metadata', async () => {
+      document.head.innerHTML = '<meta name="event-code" content="max2025">';
+      const promises = loadMepAddons();
+      expect(promises.event).to.be.a('promise');
+    });
+    it('does not load event from the legacy event-id metadata', async () => {
+      document.head.innerHTML = '<meta name="event-id" content="max2025">';
+      const promises = loadMepAddons();
+      expect(promises.event).to.be.undefined;
+    });
     afterEach(() => {
       document.head.innerHTML = '';
     });