Self hosted Webpush notification system like truepush or one signal

i went system like truepush or somthing like this larapush, i just tired of paying push services ? now i want a self hosted webpush service of my own server please help me, i hired developer earlier he did what i wanted, in 5000 rupees he give me a control panel and plugin, Where I was easily adding my wordpress website, the script is working well but the problem is that there are many shortcomings in that script like notification block in incogonito tab and chrome descktop also tells notification block And shows the same to the subsriber of 2 different websites, I told the developer about this but now he is not responding to any of my questions