diff --git a/backend/src/middleware/notifications/notificationsMiddleware.online-status.spec.ts b/backend/src/middleware/notifications/notificationsMiddleware.online-status.spec.ts
new file mode 100644
index 000000000..acc446d6b
--- /dev/null
+++ b/backend/src/middleware/notifications/notificationsMiddleware.online-status.spec.ts
@@ -0,0 +1,146 @@
+import { createTestClient } from 'apollo-server-testing'
+import gql from 'graphql-tag'
+
+import Factory, { cleanDatabase } from '@db/factories'
+import { getNeode, getDriver } from '@db/neo4j'
+import CONFIG from '@src/config'
+import createServer from '@src/server'
+
+CONFIG.CATEGORIES_ACTIVE = false
+
+const sendMailMock = jest.fn()
+jest.mock('../helpers/email/sendMail', () => ({
+  sendMail: () => sendMailMock(),
+}))
+
+let isUserOnlineMock = jest.fn().mockReturnValue(false)
+jest.mock('../helpers/isUserOnline', () => ({
+  isUserOnline: () => isUserOnlineMock(),
+}))
+
+let server, mutate, authenticatedUser
+
+let postAuthor
+
+const driver = getDriver()
+const neode = getNeode()
+
+const createPostMutation = gql`
+  mutation ($id: ID, $title: String!, $content: String!, $groupId: ID) {
+    CreatePost(id: $id, title: $title, content: $content, groupId: $groupId) {
+      id
+      title
+      content
+    }
+  }
+`
+
+beforeAll(async () => {
+  await cleanDatabase()
+
+  const createServerResult = createServer({
+    context: () => {
+      return {
+        user: authenticatedUser,
+        neode,
+        driver,
+        cypherParams: {
+          currentUserId: authenticatedUser ? authenticatedUser.id : null,
+        },
+      }
+    },
+  })
+  server = createServerResult.server
+  const createTestClientResult = createTestClient(server)
+  mutate = createTestClientResult.mutate
+})
+
+afterAll(async () => {
+  await cleanDatabase()
+  driver.close()
+})
+
+afterEach(async () => {
+  await cleanDatabase()
+})
+
+describe('online status and sending emails', () => {
+  beforeEach(async () => {
+    postAuthor = await Factory.build(
+      'user',
+      {
+        id: 'post-author',
+        name: 'Post Author',
+        slug: 'post-author',
+      },
+      {
+        email: 'test@example.org',
+        password: '1234',
+      },
+    )
+    await Factory.build(
+      'user',
+      {
+        id: 'other-user',
+        name: 'Other User',
+        slug: 'other-user',
+      },
+      {
+        email: 'test2@example.org',
+        password: '1234',
+      },
+    )
+  })
+
+  describe('user is online', () => {
+    beforeAll(() => {
+      isUserOnlineMock = jest.fn().mockReturnValue(true)
+    })
+
+    describe('mentioned in post', () => {
+      beforeEach(async () => {
+        jest.clearAllMocks()
+        authenticatedUser = await postAuthor.toJson()
+        await mutate({
+          mutation: createPostMutation,
+          variables: {
+            id: 'post-online-1',
+            title: 'This post mentions the other user',
+            content:
+              'Hello <a class="mention" data-mention-id="other-user" href="/profile/other-user/other-user">@other-user</a>, are you fine?',
+          },
+        })
+      })
+
+      it('sends NO email to the other user', () => {
+        expect(sendMailMock).not.toBeCalled()
+      })
+    })
+  })
+
+  describe('user is offline', () => {
+    beforeAll(() => {
+      isUserOnlineMock = jest.fn().mockReturnValue(false)
+    })
+
+    describe('mentioned in post', () => {
+      beforeEach(async () => {
+        jest.clearAllMocks()
+        authenticatedUser = await postAuthor.toJson()
+        await mutate({
+          mutation: createPostMutation,
+          variables: {
+            id: 'post-offline-1',
+            title: 'This post mentions the other user',
+            content:
+              'Hello <a class="mention" data-mention-id="other-user" href="/profile/other-user/other-user">@other-user</a>, are you fine?',
+          },
+        })
+      })
+
+      it('sends email to the other user', () => {
+        expect(sendMailMock).toBeCalledTimes(1)
+      })
+    })
+  })
+})
diff --git a/backend/src/middleware/notifications/notificationsMiddleware.ts b/backend/src/middleware/notifications/notificationsMiddleware.ts
index 62050b3cc..f70e9fc89 100644
--- a/backend/src/middleware/notifications/notificationsMiddleware.ts
+++ b/backend/src/middleware/notifications/notificationsMiddleware.ts
@@ -49,7 +49,10 @@ const publishNotifications = async (context, promises, emailNotificationSetting:
   )
   notifications.forEach((notificationAdded, index) => {
     pubsub.publish(NOTIFICATION_ADDED, { notificationAdded })
-    if (notificationAdded.to[emailNotificationSetting] ?? true) {
+    if (
+      (notificationAdded.to[emailNotificationSetting] ?? true) &&
+      !isUserOnline(notificationAdded.to)
+    ) {
       sendMail(
         notificationTemplate({
           email: notificationsEmailAddresses[index].email,