diff --git a/client/coral-framework/hocs/index.js b/client/coral-framework/hocs/index.js
index 97bf910d9..e16e09941 100644
--- a/client/coral-framework/hocs/index.js
+++ b/client/coral-framework/hocs/index.js
@@ -18,6 +18,7 @@ export { default as withVariables } from './withVariables';
 export { default as WithRefetch } from './withRefetch';
 export { default as withFetchMore } from './withFetchMore';
 export { default as withSubscribeToMore } from './withSubscribeToMore';
+export { default as withGraphQLExtension } from './withGraphQLExtension';
 export {
   default as withResendEmailConfirmation,
 } from './withResendEmailConfirmation';
diff --git a/client/coral-framework/hocs/withGraphQLExtension.js b/client/coral-framework/hocs/withGraphQLExtension.js
new file mode 100644
index 000000000..c44a94e47
--- /dev/null
+++ b/client/coral-framework/hocs/withGraphQLExtension.js
@@ -0,0 +1,19 @@
+import React from 'react';
+import hoistStatics from 'recompose/hoistStatics';
+
+/**
+ * WithGraphQLExtension adds graphql configuration to the
+ * GraphQL registry, only works on Components used
+ * directly in a Slot.
+ */
+export default extension =>
+  hoistStatics(WrappedComponent => {
+    class WithGraphQLExtension extends React.Component {
+      render() {
+        return <WrappedComponent {...this.props} />;
+      }
+    }
+
+    WrappedComponent.graphqlExtension = extension;
+    return WithGraphQLExtension;
+  });
diff --git a/client/coral-framework/services/plugins.js b/client/coral-framework/services/plugins.js
index 3879249ac..b390f1a1b 100644
--- a/client/coral-framework/services/plugins.js
+++ b/client/coral-framework/services/plugins.js
@@ -7,6 +7,7 @@ import isEmpty from 'lodash/isEmpty';
 import flatten from 'lodash/flatten';
 import mapValues from 'lodash/mapValues';
 import get from 'lodash/get';
+import values from 'lodash/values';
 import { getDisplayName } from 'coral-framework/helpers/hoc';
 import camelize from '../helpers/camelize';
 
@@ -205,9 +206,16 @@ class PluginsService {
   }
 
   getGraphQLExtensions() {
-    return this.plugins
-      .map(o => pick(o.module, ['mutations', 'queries', 'fragments']))
-      .filter(o => !isEmpty(o));
+    return flatten(
+      this.plugins.map(o => {
+        const extension = pick(o.module, ['mutations', 'queries', 'fragments']);
+        // Include extension defined in Slot Components.
+        const slotComponentExtensions = !o.module.slots
+          ? []
+          : flatten(values(o.module.slots)).map(cmp => cmp.graphqlExtension);
+        return [extension, ...slotComponentExtensions];
+      })
+    ).filter(o => !isEmpty(o));
   }
 
   getModQueueConfigs() {
diff --git a/plugin-api/beta/client/hocs/index.js b/plugin-api/beta/client/hocs/index.js
index ff4523084..215641f32 100644
--- a/plugin-api/beta/client/hocs/index.js
+++ b/plugin-api/beta/client/hocs/index.js
@@ -17,6 +17,7 @@ export {
   withFetchMore,
   withSubscribeToMore,
   withRefetch,
+  withGraphQLExtension,
 } from 'coral-framework/hocs';
 export {
   withIgnoreUser,
diff --git a/plugins/talk-plugin-notifications-category-reply/client/containers/Toggle.js b/plugins/talk-plugin-notifications-category-reply/client/containers/Toggle.js
index d261946d0..c55be5f90 100644
--- a/plugins/talk-plugin-notifications-category-reply/client/containers/Toggle.js
+++ b/plugins/talk-plugin-notifications-category-reply/client/containers/Toggle.js
@@ -3,7 +3,10 @@ import PropTypes from 'prop-types';
 import { compose, gql } from 'react-apollo';
 import Toggle from 'talk-plugin-notifications/client/components/Toggle';
 import { t } from 'plugin-api/beta/client/services';
-import { withFragments } from 'plugin-api/beta/client/hocs';
+import {
+  withFragments,
+  withGraphQLExtension,
+} from 'plugin-api/beta/client/hocs';
 
 class ToggleContainer extends React.Component {
   constructor(props) {
@@ -57,6 +60,38 @@ ToggleContainer.propTypes = {
   disabled: PropTypes.bool.isRequired,
 };
 
+const extension = {
+  mutations: {
+    UpdateNotificationSettings: ({
+      variables: { input },
+      state: { auth: { user: { id } } },
+    }) => ({
+      update: proxy => {
+        if (input.onReply === undefined) {
+          return;
+        }
+
+        const fragment = gql`
+          fragment TalkNotificationsCategoryReply_User_Fragment on User {
+            notificationSettings {
+              onReply
+            }
+          }
+        `;
+        const fragmentId = `User_${id}`;
+        const data = {
+          __typename: 'User',
+          notificationSettings: {
+            __typename: 'NotificationSettings',
+            onReply: input.onReply,
+          },
+        };
+        proxy.writeFragment({ fragment, id: fragmentId, data });
+      },
+    }),
+  },
+};
+
 const enhance = compose(
   withFragments({
     root: gql`
@@ -68,7 +103,8 @@ const enhance = compose(
         }
       }
     `,
-  })
+  }),
+  withGraphQLExtension(extension)
 );
 
 export default enhance(ToggleContainer);
diff --git a/plugins/talk-plugin-notifications-category-reply/client/index.js b/plugins/talk-plugin-notifications-category-reply/client/index.js
index 1e22c3a93..fa10c15e2 100644
--- a/plugins/talk-plugin-notifications-category-reply/client/index.js
+++ b/plugins/talk-plugin-notifications-category-reply/client/index.js
@@ -1,11 +1,8 @@
 import Toggle from './containers/Toggle';
 import translations from './translations.yml';
-import graphql from './graphql';
-
 export default {
   slots: {
     notificationSettings: [Toggle],
   },
   translations,
-  ...graphql,
 };