diff --git a/addons/mail/static/src/core/common/messaging_service.js b/addons/mail/static/src/core/common/messaging_service.js
index 10e1288e780..72a1a9e9c61 100644
--- a/addons/mail/static/src/core/common/messaging_service.js
+++ b/addons/mail/static/src/core/common/messaging_service.js
@@ -27,8 +27,6 @@ export class Messaging {
         this.store = services["mail.store"];
         this.rpc = services.rpc;
         this.orm = services.orm;
-        /** @type {import("@mail/core/common/channel_member_service").ChannelMemberService} */
-        this.channelMemberService = services["discuss.channel.member"];
         /** @type {import("@mail/core/common/attachment_service").AttachmentService} */
         this.attachmentService = services["mail.attachment"];
         this.notificationService = services.notification;
@@ -40,11 +38,8 @@ export class Messaging {
         this.messageService = services["mail.message"];
         /** @type {import("@mail/core/common/persona_service").PersonaService} */
         this.personaService = services["mail.persona"];
-        /** @type {import("@mail/core/common/out_of_focus_service").OutOfFocusService} */
-        this.outOfFocusService = services["mail.out_of_focus"];
         this.router = services.router;
         this.bus = services.bus_service;
-        this.presence = services.presence;
         this.isReady = new Deferred();
         this.imStatusService = services.im_status;
         const user = services.user;
@@ -158,14 +153,6 @@ export class Messaging {
     // -------------------------------------------------------------------------
 
     handleNotification(notifications) {
-        const channelsLeft = new Set(
-            notifications.reduce((channelIds, notification) => {
-                if (notification.type === "discuss.channel/leave") {
-                    channelIds.push(notification.payload.id);
-                }
-                return channelIds;
-            }, [])
-        );
         for (const notif of notifications) {
             switch (notif.type) {
                 case "mail.activity/updated":
@@ -176,17 +163,6 @@ export class Messaging {
                         this.store.activityCounter--;
                     }
                     break;
-                case "discuss.channel/new_message":
-                    if (channelsLeft.has(notif.payload.id)) {
-                        // Do not handle new message notification if the channel
-                        // was just left. This issue occurs because the
-                        // "discuss.channel/leave" and the
-                        // "discuss.channel/new_message" notifications come from
-                        // the bus as a batch.
-                        break;
-                    }
-                    this._handleNotificationNewMessage(notif);
-                    break;
                 case "discuss.channel/leave":
                     {
                         const thread = this.threadService.insert({
@@ -446,87 +422,6 @@ export class Messaging {
         }
     }
 
-    async _handleNotificationNewMessage(notif) {
-        const { id, message: messageData } = notif.payload;
-        let channel = this.store.threads[createLocalId("discuss.channel", id)];
-        if (!channel || !channel.type) {
-            const [channelData] = await this.rpc("/discuss/channel/info", { channel_id: id });
-            channel = this.threadService.insert({
-                model: "discuss.channel",
-                type: channelData.channel.channel_type,
-                ...channelData,
-            });
-        }
-        if (!channel.is_pinned) {
-            this.threadService.pin(channel);
-        }
-
-        removeFromArrayWithPredicate(channel.messages, ({ id }) => id === messageData.temporary_id);
-        delete this.store.messages[messageData.temporary_id];
-        messageData.temporary_id = null;
-        if ("parentMessage" in messageData && messageData.parentMessage.body) {
-            messageData.parentMessage.body = markup(messageData.parentMessage.body);
-        }
-        const data = Object.assign(messageData, {
-            body: markup(messageData.body),
-        });
-        const message = this.messageService.insert({
-            ...data,
-            res_id: channel.id,
-            model: channel.model,
-        });
-        if (!channel.messages.includes(message)) {
-            if (!channel.loadNewer) {
-                channel.messages.push(message);
-            } else if (channel.state === "loading") {
-                channel.pendingNewMessages.push(message);
-            }
-            if (message.isSelfAuthored) {
-                channel.seen_message_id = message.id;
-            } else {
-                if (notif.id > this.store.initBusId) {
-                    channel.message_unread_counter++;
-                }
-                if (message.isNeedaction) {
-                    const inbox = this.store.discuss.inbox;
-                    if (!inbox.messages.includes(message)) {
-                        inbox.messages.push(message);
-                        if (notif.id > this.store.initBusId) {
-                            inbox.counter++;
-                        }
-                    }
-                    if (!channel.needactionMessages.includes(message)) {
-                        channel.needactionMessages.push(message);
-                        if (notif.id > this.store.initBusId) {
-                            channel.message_needaction_counter++;
-                        }
-                    }
-                }
-            }
-        }
-        if (channel.chatPartnerId !== this.store.odoobot?.id) {
-            if (!this.presence.isOdooFocused() && channel.isChatChannel) {
-                this.outOfFocusService.notify(message, channel);
-            }
-
-            if (channel.type !== "channel" && !this.store.guest) {
-                // disabled on non-channel threads and
-                // on "channel" channels for performance reasons
-                this.threadService.markAsFetched(channel);
-            }
-        }
-        if (
-            !channel.loadNewer &&
-            !message.isSelfAuthored &&
-            channel.composer.isFocused &&
-            channel.newestPersistentMessage &&
-            !this.store.guest &&
-            channel.newestPersistentMessage === channel.newestMessage
-        ) {
-            this.threadService.markAsRead(channel);
-        }
-    }
-
     _handleNotificationRecordInsert(notif) {
         if (notif.payload.Thread) {
             this.threadService.insert(notif.payload.Thread);
@@ -652,7 +547,6 @@ export class Messaging {
 export const messagingService = {
     dependencies: [
         "mail.store",
-        "discuss.channel.member",
         "rpc",
         "orm",
         "user",
@@ -660,13 +554,11 @@ export const messagingService = {
         "bus_service",
         "im_status",
         "notification",
-        "presence",
         "mail.attachment",
         "mail.user_settings",
         "mail.thread",
         "mail.message",
         "mail.persona",
-        "mail.out_of_focus",
     ],
     start(env, services) {
         const messaging = new Messaging(env, services);
diff --git a/addons/mail/static/src/core/web/messaging_service_patch.js b/addons/mail/static/src/core/web/messaging_service_patch.js
index 9025f0d1b66..52fd4b37325 100644
--- a/addons/mail/static/src/core/web/messaging_service_patch.js
+++ b/addons/mail/static/src/core/web/messaging_service_patch.js
@@ -1,7 +1,6 @@
 /* @odoo-module */
 
 import { Messaging, messagingService } from "@mail/core/common/messaging_service";
-import { createLocalId } from "@mail/utils/common/misc";
 
 import { _t } from "@web/core/l10n/translation";
 import { patch } from "@web/core/utils/patch";
@@ -42,18 +41,6 @@ patch(Messaging.prototype, "mail/core/web", {
         }
         this._super(data);
     },
-    async _handleNotificationNewMessage(notif) {
-        await this._super(notif);
-        const channel = this.store.threads[createLocalId("discuss.channel", notif.payload.id)];
-        const message = this.store.messages[notif.payload.message.id];
-        if (
-            !this.ui.isSmall &&
-            channel.correspondent !== this.store.odoobot &&
-            !message.isSelfAuthored
-        ) {
-            this.chatWindowService.insert({ thread: channel });
-        }
-    },
 });
 
 patch(messagingService, "mail/core/web", {
diff --git a/addons/mail/static/src/discuss/core/common/discuss_core_common_service.js b/addons/mail/static/src/discuss/core/common/discuss_core_common_service.js
new file mode 100644
index 00000000000..eadd2ff4eae
--- /dev/null
+++ b/addons/mail/static/src/discuss/core/common/discuss_core_common_service.js
@@ -0,0 +1,152 @@
+/* @odoo-module */
+
+import { removeFromArrayWithPredicate } from "@mail/utils/common/arrays";
+import { createLocalId } from "@mail/utils/common/misc";
+
+import { markup, reactive } from "@odoo/owl";
+
+import { registry } from "@web/core/registry";
+
+export class DiscussCoreCommon {
+    constructor(env, services) {
+        Object.assign(this, {
+            busService: services.bus_service,
+            env,
+            presence: services.presence,
+            rpc: services.rpc,
+        });
+        /** @type {import("@mail/core/common/message_service").MessageService} */
+        this.messageService = services["mail.message"];
+        /** @type {import("@mail/core/common/messaging_service").Messaging} */
+        this.messagingService = services["mail.messaging"];
+        /** @type {import("@mail/core/common/out_of_focus_service").OutOfFocusService} */
+        this.outOfFocusService = services["mail.out_of_focus"];
+        /** @type {import("@mail/core/common/thread_service").ThreadService} */
+        this.threadService = services["mail.thread"];
+        /** @type {import("@mail/core/common/store_service").Store} */
+        this.store = services["mail.store"];
+    }
+
+    setup() {
+        this.messagingService.isReady.then(() => {
+            this.busService.addEventListener("notification", ({ detail: notifications }) => {
+                // Do not handle new message notification if the channel was just left. This issue
+                // occurs because the "discuss.channel/leave" and the "discuss.channel/new_message"
+                // notifications come from the bus as a batch.
+                const channelsLeft = new Set(
+                    notifications
+                        .filter(({ type }) => type === "discuss.channel/leave")
+                        .map(({ payload }) => payload.id)
+                );
+                for (const notif of notifications.filter(
+                    ({ payload, type }) =>
+                        type === "discuss.channel/new_message" && !channelsLeft.has(payload.id)
+                )) {
+                    this._handleNotificationNewMessage(notif);
+                }
+            });
+            this.busService.start();
+        });
+    }
+
+    async _handleNotificationNewMessage(notif) {
+        const { id, message: messageData } = notif.payload;
+        let channel = this.store.threads[createLocalId("discuss.channel", id)];
+        if (!channel || !channel.type) {
+            const [channelData] = await this.rpc("/discuss/channel/info", { channel_id: id });
+            channel = this.threadService.insert({
+                model: "discuss.channel",
+                type: channelData.channel.channel_type,
+                ...channelData,
+            });
+        }
+        if (!channel.is_pinned) {
+            this.threadService.pin(channel);
+        }
+        removeFromArrayWithPredicate(channel.messages, ({ id }) => id === messageData.temporary_id);
+        delete this.store.messages[messageData.temporary_id];
+        messageData.temporary_id = null;
+        if ("parentMessage" in messageData && messageData.parentMessage.body) {
+            messageData.parentMessage.body = markup(messageData.parentMessage.body);
+        }
+        const data = Object.assign(messageData, {
+            body: markup(messageData.body),
+        });
+        const message = this.messageService.insert({
+            ...data,
+            res_id: channel.id,
+            model: channel.model,
+        });
+        if (!channel.messages.includes(message)) {
+            if (!channel.loadNewer) {
+                channel.messages.push(message);
+            } else if (channel.state === "loading") {
+                channel.pendingNewMessages.push(message);
+            }
+            if (message.isSelfAuthored) {
+                channel.seen_message_id = message.id;
+            } else {
+                if (notif.id > this.store.initBusId) {
+                    channel.message_unread_counter++;
+                }
+                if (message.isNeedaction) {
+                    const inbox = this.store.discuss.inbox;
+                    if (!inbox.messages.includes(message)) {
+                        inbox.messages.push(message);
+                        if (notif.id > this.store.initBusId) {
+                            inbox.counter++;
+                        }
+                    }
+                    if (!channel.needactionMessages.includes(message)) {
+                        channel.needactionMessages.push(message);
+                        if (notif.id > this.store.initBusId) {
+                            channel.message_needaction_counter++;
+                        }
+                    }
+                }
+            }
+        }
+        if (channel.chatPartnerId !== this.store.odoobot?.id) {
+            if (!this.presence.isOdooFocused() && channel.isChatChannel) {
+                this.outOfFocusService.notify(message, channel);
+            }
+
+            if (channel.type !== "channel" && !this.store.guest) {
+                // disabled on non-channel threads and
+                // on "channel" channels for performance reasons
+                this.threadService.markAsFetched(channel);
+            }
+        }
+        if (
+            !channel.loadNewer &&
+            !message.isSelfAuthored &&
+            channel.composer.isFocused &&
+            channel.newestPersistentMessage &&
+            !this.store.guest &&
+            channel.newestPersistentMessage === channel.newestMessage
+        ) {
+            this.threadService.markAsRead(channel);
+        }
+        this.env.bus.trigger("discuss.channel/new_message", { channel, message });
+    }
+}
+
+export const discussCoreCommon = {
+    dependencies: [
+        "bus_service",
+        "mail.message",
+        "mail.messaging",
+        "mail.out_of_focus",
+        "mail.store",
+        "mail.thread",
+        "presence",
+        "rpc",
+    ],
+    start(env, services) {
+        const discussCoreCommon = reactive(new DiscussCoreCommon(env, services));
+        discussCoreCommon.setup();
+        return discussCoreCommon;
+    },
+};
+
+registry.category("services").add("discuss.core.common", discussCoreCommon);
diff --git a/addons/mail/static/src/discuss/core/web/discuss_core_web_service.js b/addons/mail/static/src/discuss/core/web/discuss_core_web_service.js
new file mode 100644
index 00000000000..c4ec289391f
--- /dev/null
+++ b/addons/mail/static/src/discuss/core/web/discuss_core_web_service.js
@@ -0,0 +1,41 @@
+/* @odoo-module */
+
+import { reactive } from "@odoo/owl";
+
+import { registry } from "@web/core/registry";
+
+export class DiscussCoreWeb {
+    constructor(env, services) {
+        Object.assign(this, { env, ui: services.ui });
+        /** @type {import("@mail/core/common/chat_window_service").ChatWindowService} */
+        this.chatWindowService = services["mail.chat_window"];
+        /** @type {import("@mail/core/common/store_service").Store} */
+        this.store = services["mail.store"];
+    }
+
+    setup() {
+        this.env.bus.addEventListener(
+            "discuss.channel/new_message",
+            ({ detail: { channel, message } }) => {
+                if (
+                    !this.ui.isSmall &&
+                    channel.correspondent !== this.store.odoobot &&
+                    !message.isSelfAuthored
+                ) {
+                    this.chatWindowService.insert({ thread: channel });
+                }
+            }
+        );
+    }
+}
+
+export const discussCoreWeb = {
+    dependencies: ["mail.chat_window", "mail.store", "ui"],
+    start(env, services) {
+        const discussCoreWeb = reactive(new DiscussCoreWeb(env, services));
+        discussCoreWeb.setup();
+        return discussCoreWeb;
+    },
+};
+
+registry.category("services").add("discuss.core.web", discussCoreWeb);
diff --git a/addons/mail/static/tests/helpers/discuss/core/common/setup_manager_patch.js b/addons/mail/static/tests/helpers/discuss/core/common/setup_manager_patch.js
new file mode 100644
index 00000000000..d12c5599edc
--- /dev/null
+++ b/addons/mail/static/tests/helpers/discuss/core/common/setup_manager_patch.js
@@ -0,0 +1,15 @@
+/* @odoo-module */
+
+import { discussCoreCommon } from "@mail/discuss/core/common/discuss_core_common_service";
+import { setupManager } from "@mail/../tests/helpers/webclient_setup";
+
+import { patch } from "@web/core/utils/patch";
+
+patch(setupManager, "discuss/core/common", {
+    setupServices(...args) {
+        return {
+            ...this._super(...args),
+            "discuss.core.common": discussCoreCommon,
+        };
+    },
+});
diff --git a/addons/mail/static/tests/helpers/discuss/core/web/setup_manager_patch.js b/addons/mail/static/tests/helpers/discuss/core/web/setup_manager_patch.js
new file mode 100644
index 00000000000..08cf8a8ef00
--- /dev/null
+++ b/addons/mail/static/tests/helpers/discuss/core/web/setup_manager_patch.js
@@ -0,0 +1,15 @@
+/* @odoo-module */
+
+import { discussCoreWeb } from "@mail/discuss/core/web/discuss_core_web_service";
+import { setupManager } from "@mail/../tests/helpers/webclient_setup";
+
+import { patch } from "@web/core/utils/patch";
+
+patch(setupManager, "discuss/core/web", {
+    setupServices(...args) {
+        return {
+            ...this._super(...args),
+            "discuss.core.web": discussCoreWeb,
+        };
+    },
+});