diff --git a/changelog/unreleased/enhancement-sse-get-notifications-instantly b/changelog/unreleased/enhancement-sse-get-notifications-instantly
new file mode 100644
index 00000000000..e6c0d4039d4
--- /dev/null
+++ b/changelog/unreleased/enhancement-sse-get-notifications-instantly
@@ -0,0 +1,8 @@
+Enhancement: Add SSE to get notifications instantly
+
+We've added SSE to the notifications which allows us to be notified
+about new notifications instantly and from the server without polling
+every few seconds.
+
+https://github.com/owncloud/web/pull/9451
+https://github.com/owncloud/web/issues/9434
diff --git a/packages/web-pkg/package.json b/packages/web-pkg/package.json
index dae274c7604..a33427230dd 100644
--- a/packages/web-pkg/package.json
+++ b/packages/web-pkg/package.json
@@ -14,6 +14,7 @@
     "directory": "packages/web-pkg"
   },
   "peerDependencies": {
+    "@microsoft/fetch-event-source": "^2.0.1",
     "@casl/ability": "^6.3.3",
     "@casl/vue": "^2.2.1",
     "axios": "^0.27.2 || ^1.0.0",
diff --git a/packages/web-pkg/src/composables/capability/useCapability.ts b/packages/web-pkg/src/composables/capability/useCapability.ts
index 8ad5987fa5f..8df471becdf 100644
--- a/packages/web-pkg/src/composables/capability/useCapability.ts
+++ b/packages/web-pkg/src/composables/capability/useCapability.ts
@@ -29,6 +29,7 @@ export const useCapabilityCoreSupportUrlSigning = createCapabilityComposable(
   'core.support-url-signing',
   false
 )
+export const useCapabilityCoreSSE = createCapabilityComposable('core.support-sse', false)
 export const useCapabilityGraphPersonalDataExport = createCapabilityComposable(
   'graph.personal-data-export',
   false
diff --git a/packages/web-pkg/src/composables/index.ts b/packages/web-pkg/src/composables/index.ts
index 5df6c8734cb..10f6ddd97e9 100644
--- a/packages/web-pkg/src/composables/index.ts
+++ b/packages/web-pkg/src/composables/index.ts
@@ -17,3 +17,4 @@ export * from './store'
 export * from './fileListHeaderPosition'
 export * from './viewMode'
 export * from './search'
+export * from './sse'
diff --git a/packages/web-pkg/src/composables/sse/index.ts b/packages/web-pkg/src/composables/sse/index.ts
new file mode 100644
index 00000000000..f12353de45e
--- /dev/null
+++ b/packages/web-pkg/src/composables/sse/index.ts
@@ -0,0 +1 @@
+export * from './useServerSentEvents'
diff --git a/packages/web-pkg/src/composables/sse/useServerSentEvents.ts b/packages/web-pkg/src/composables/sse/useServerSentEvents.ts
new file mode 100644
index 00000000000..0f64b2e5030
--- /dev/null
+++ b/packages/web-pkg/src/composables/sse/useServerSentEvents.ts
@@ -0,0 +1,64 @@
+import { EventSourceMessage, fetchEventSource } from '@microsoft/fetch-event-source'
+import { ref, unref, watch } from 'vue'
+import { v4 as uuidV4 } from 'uuid'
+import { useGettext } from 'vue3-gettext'
+import { configurationManager, useAccessToken, useStore } from 'web-pkg/src'
+
+export interface ServerSentEventsOptions {
+  url: string
+  onOpen?: (response: Response) => void
+  onMessage?: (msg: EventSourceMessage) => void
+}
+
+export const useServerSentEvents = (options: ServerSentEventsOptions) => {
+  const store = useStore()
+  const language = useGettext()
+  const accessToken = useAccessToken({ store })
+  const ctrl = ref(new AbortController())
+  const retryCounter = ref(0)
+
+  watch(
+    () => language.current,
+    () => {
+      unref(ctrl).abort()
+    }
+  )
+  const setupServerSentEvents = () => {
+    if (unref(retryCounter) >= 5) {
+      unref(ctrl).abort()
+      throw new Error('Too many retries')
+    }
+    const setupSSE = async () => {
+      retryCounter.value++
+      try {
+        ctrl.value = new AbortController()
+        await fetchEventSource(new URL(options.url, configurationManager.serverUrl).href, {
+          signal: unref(ctrl).signal,
+          headers: {
+            Authorization: `Bearer ${accessToken.value}`,
+            'Accept-Language': unref(language).current,
+            'X-Request-ID': uuidV4()
+          },
+          async onopen(response) {
+            if (response.status === 401) {
+              unref(ctrl).abort()
+              return
+            }
+            retryCounter.value = 0
+            await options.onOpen?.(response)
+          },
+          onmessage(msg) {
+            options.onMessage?.(msg)
+          }
+        })
+      } catch (e) {
+        console.error(e)
+      }
+    }
+    setupSSE().then(() => {
+      setupServerSentEvents()
+    })
+  }
+
+  return setupServerSentEvents
+}
diff --git a/packages/web-runtime/src/components/Topbar/Notifications.vue b/packages/web-runtime/src/components/Topbar/Notifications.vue
index 4dfd6cf0d71..36415662373 100644
--- a/packages/web-runtime/src/components/Topbar/Notifications.vue
+++ b/packages/web-runtime/src/components/Topbar/Notifications.vue
@@ -98,7 +98,9 @@ import {
   formatRelativeDateFromISO,
   useClientService,
   useRoute,
-  useStore
+  useStore,
+  useServerSentEvents,
+  useCapabilityCoreSSE
 } from 'web-pkg'
 import { useGettext } from 'vue3-gettext'
 import { useTask } from 'vue-concurrency'
@@ -121,6 +123,30 @@ export default {
     const notificationsInterval = ref()
     const dropdownOpened = ref(false)
 
+    const sseEnabled = useCapabilityCoreSSE()
+    let setupServerSentEvents
+    if (unref(sseEnabled)) {
+      setupServerSentEvents = useServerSentEvents({
+        url: 'ocs/v2.php/apps/notifications/api/v1/notifications/sse',
+        onOpen: (response): void => {
+          fetchNotificationsTask.perform()
+          if (!response.ok) {
+            console.error(`SSE notifications couldn't be set up ${response.status}`)
+          }
+        },
+        onMessage: (msg): void => {
+          if (msg.event === 'FatalError') {
+            console.error(`SSE notifications error: ${msg.data}`)
+            return
+          }
+          const data = JSON.parse(msg.data)
+          if (data.notification_id) {
+            notifications.value = [data, ...unref(notifications)]
+          }
+        }
+      })
+    }
+
     const formatDate = (date) => {
       return formatDateFromISO(date, currentLanguage)
     }
@@ -291,11 +317,15 @@ export default {
       setAdditionalData()
     }
 
-    onMounted(() => {
-      fetchNotificationsTask.perform()
-      notificationsInterval.value = setInterval(() => {
+    onMounted(async () => {
+      if (unref(sseEnabled)) {
+        await setupServerSentEvents()
+      } else {
+        notificationsInterval.value = setInterval(() => {
+          fetchNotificationsTask.perform()
+        }, POLLING_INTERVAL)
         fetchNotificationsTask.perform()
-      }, POLLING_INTERVAL)
+      }
     })
 
     onUnmounted(() => {
diff --git a/packages/web-runtime/tests/unit/components/Topbar/Notifications.spec.ts b/packages/web-runtime/tests/unit/components/Topbar/Notifications.spec.ts
index 07789b22b2c..b20baf70fc9 100644
--- a/packages/web-runtime/tests/unit/components/Topbar/Notifications.spec.ts
+++ b/packages/web-runtime/tests/unit/components/Topbar/Notifications.spec.ts
@@ -24,6 +24,8 @@ const selectors = {
   notificationActions: '.oc-notifications-actions'
 }
 
+jest.mock('web-pkg/src/composables/sse/useServerSentEvents')
+
 describe('Notification component', () => {
   it('renders the notification bell and no notifications if there are none', () => {
     const { wrapper } = getWrapper()
@@ -34,6 +36,7 @@ describe('Notification component', () => {
   it('renders a set of notifications', async () => {
     const notifications = [mock<Notification>({ messageRich: undefined })]
     const { wrapper } = getWrapper({ notifications })
+    await wrapper.vm.fetchNotificationsTask.perform()
     await wrapper.vm.fetchNotificationsTask.last
     expect(wrapper.find(selectors.noNewNotifications).exists()).toBeFalsy()
     expect(wrapper.findAll(selectors.notificationItem).length).toBe(notifications.length)
@@ -41,6 +44,7 @@ describe('Notification component', () => {
   it('renders the loading state', async () => {
     const notifications = [mock<Notification>({ messageRich: undefined })]
     const { wrapper } = getWrapper({ notifications })
+    await wrapper.vm.fetchNotificationsTask.perform()
     await wrapper.vm.fetchNotificationsTask.last
     wrapper.vm.loading = true
     await wrapper.vm.$nextTick()
@@ -49,10 +53,11 @@ describe('Notification component', () => {
   it('marks all notifications as read', async () => {
     const notifications = [mock<Notification>({ messageRich: undefined })]
     const { wrapper, mocks } = getWrapper({ notifications })
+    await wrapper.vm.fetchNotificationsTask.perform()
     await wrapper.vm.fetchNotificationsTask.last
     await wrapper.find(selectors.markAll).trigger('click')
     expect(wrapper.find(selectors.notificationItem).exists()).toBeFalsy()
-    expect(mocks.$clientService.owncloudSdk.requests.ocs).toHaveBeenCalledTimes(2)
+    expect(mocks.$clientService.owncloudSdk.requests.ocs).toHaveBeenCalledTimes(3)
   })
   describe('avatar', () => {
     it('loads based on the username', async () => {
@@ -61,6 +66,7 @@ describe('Notification component', () => {
         user: 'einstein'
       })
       const { wrapper } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       const avatarImageStub = wrapper.findComponent<any>(selectors.avatarImageStub)
       expect(avatarImageStub.attributes('userid')).toEqual(notification.user)
@@ -74,6 +80,7 @@ describe('Notification component', () => {
         messageRichParameters: { user: { displayname, name } }
       })
       const { wrapper } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       const avatarImageStub = wrapper.findComponent<any>(selectors.avatarImageStub)
       expect(avatarImageStub.attributes('userid')).toEqual(name)
@@ -87,6 +94,7 @@ describe('Notification component', () => {
         message: undefined
       })
       const { wrapper } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       expect(wrapper.find(selectors.notificationSubject).exists()).toBeTruthy()
     })
@@ -98,6 +106,7 @@ describe('Notification component', () => {
         message: 'some message'
       })
       const { wrapper } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       wrapper.vm.showDrop()
       await wrapper.vm.$nextTick()
@@ -112,6 +121,7 @@ describe('Notification component', () => {
         }
       })
       const { wrapper } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       wrapper.vm.showDrop()
       await wrapper.vm.$nextTick()
@@ -127,6 +137,7 @@ describe('Notification component', () => {
         link: 'http://some-link.com'
       })
       const { wrapper } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       expect(wrapper.find(selectors.notificationLink).exists()).toBeTruthy()
     })
@@ -142,6 +153,7 @@ describe('Notification component', () => {
           }
         })
         const { wrapper } = getWrapper({ notifications: [notification] })
+        await wrapper.vm.fetchNotificationsTask.perform()
         await wrapper.vm.fetchNotificationsTask.last
         wrapper.vm.showDrop()
         await wrapper.vm.$nextTick()
@@ -168,6 +180,7 @@ describe('Notification component', () => {
           }
         })
         const { wrapper } = getWrapper({ notifications: [notification], spaces: [spaceMock] })
+        await wrapper.vm.fetchNotificationsTask.perform()
         await wrapper.vm.fetchNotificationsTask.last
         wrapper.vm.showDrop()
         await wrapper.vm.$nextTick()
@@ -187,6 +200,7 @@ describe('Notification component', () => {
         actions: [mock<NotificationAction>()]
       })
       const { wrapper } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       expect(wrapper.find(selectors.notificationActions).exists()).toBeTruthy()
     })
@@ -197,6 +211,7 @@ describe('Notification component', () => {
         actions: [mock<NotificationAction>({ link: 'http://some-link.com' })]
       })
       const { wrapper, mocks } = getWrapper({ notifications: [notification] })
+      await wrapper.vm.fetchNotificationsTask.perform()
       await wrapper.vm.fetchNotificationsTask.last
       expect(wrapper.find(selectors.notificationItem).exists()).toBeTruthy()
       const jsonResponse = {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index a3f425e96f3..f4dc3bec52b 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1,4 +1,4 @@
-lockfileVersion: '6.0'
+lockfileVersion: '6.1'
 
 settings:
   autoInstallPeers: true
@@ -907,6 +907,9 @@ importers:
       '@casl/vue':
         specifier: ^2.2.1
         version: 2.2.1(@casl/ability@6.3.3)(vue@3.3.4)
+      '@microsoft/fetch-event-source':
+        specifier: ^2.0.1
+        version: 2.0.1
       axios:
         specifier: ^0.27.2 || ^1.0.0
         version: 1.4.0
@@ -5845,6 +5848,10 @@ packages:
       '@lezer/common': 1.0.3
     dev: true
 
+  /@microsoft/fetch-event-source@2.0.1:
+    resolution: {integrity: sha512-W6CLUJ2eBMw3Rec70qrsEW0jOm/3twwJv21mrmj2yORiaVmVYGS4sSS5yUwvQc1ZlDLYGPnClVWmUUMagKNsfA==}
+    dev: false
+
   /@nicolo-ribaudo/eslint-scope-5-internals@5.1.1-v1:
     resolution: {integrity: sha512-54/JRvkLIzzDWshCWfuhadfrfZVPiElY8Fcgmg1HroEly/EDSszzhBAsarCux+D/kOslTRquNzuyGSmUSTTHGg==}
     dependencies: