Hello Odoo Community,

I'm working on Odoo 17 and trying to send a real-time notification to the Point of Sale (POS) interface using the bus.bus service.

 My goal:

When an admin user presses a button (from backend), a message should be pushed to all open POS sessions so that the cashier sees a notification popup on their screen.

 What I tried:

1. POS Frontend Code (Patch):

/** @odoo-module **/
import { patch } from "@web/core/utils/patch";
import { ProductScreen } from "@point_of_sale/app/screens/product_screen/product_screen";

patch(ProductScreen.prototype, {
    setup() {
        super.setup();
        const bus_service = this.env.services.bus_service;
        const notification = this.env.services.notification;

        const channel = JSON.stringify(["pos.custom.notification", "global"]);
        bus_service.addChannel(channel);

        onMounted(() => {
            bus_service.addEventListener("notification", ({ detail }) => {
                for (const { type, payload } of detail) {
                    if (type === "custom_alert") {
                        notification.add(payload.message, {
                            title: payload.title || "POS Notice",
                            type: "info",
                        });
                    }
                }
            });
        });
    },
});

2. Python Backend Code:

python
from odoo import models, _
from odoo.exceptions import UserError

class ResUsers(models.Model):
    _inherit = 'res.users'

    def action_notify_pos_cashier(self):
        self.env['bus.bus']._sendone(
            (self.env.cr.dbname, 'pos.custom.notification', 'global'),
            self.env.uid,
            {
                'type': 'custom_alert',
                'title': '🔔 POS Alert',
                'message': '📢 Hello from the backend!'
            }
        )


 What’s happening:

• 
  I see in the browser console that the POS is subscribed to the correct channel.
• 
  However, when I call the backend method (action_notify_pos_cashier()), nothing is received on the frontend.
• 
  No errors are shown in the frontend, and the channel is active.

My Question:

What is the correct way to structure a real-time notification from the backend to POS using bus.bus in Odoo 17 (OWL2 + POS OWL)?

Am I missing something in how the channel should be defined or how the payload is passed?

Additional info:

• 
  Odoo version: 17.0 (Community)
• 
  
  

JS code loaded via custom module using patch

Any guidance or working example would be greatly appreciated 🙏