Chat App as part of a Community (FullStack)

We are looking for a fullstack javascript developer, who has already experience with chats, chatsystems, messengers, messaging systems projects or someone who built already his own chat. The best case would be that you already have built a chat based on GraphQL subscriptions and / or websockets and Redis (PubSub Server). We would like either to buy a licence of your code, so that we can reuse it within our platform as a starting point with the ability to adapt, to merge or to extend it with or on our project or to hire you by using main components that you have built. We dont want to reinvent the wheel. The app logic should be separated from the frontend, the reuse it with another FE (Reactive Native) on a later stage. The chat should be responsive (web app), and the appearance should be similar like the webversion of the Facebook Chat (Left a contact list, middle chat thread related to a contact, right user infos, similar to whatsapp in its structure also like the webversion of whatsapp messenger but without that amount of features) More details we will share with you after our first exchange. The chat should not be used for Support Purpose it should used for user who write each other within a community. Experience and knowledge with these stacks would be appreciate: ReactJS NextJS NodeJS NestJS Apollo Server GraphQL PostgreSQL Redis Typescript PubSub Server Load Balancing