It's is an Apollo Graphql Server created using typescript which uses postgres as it's database. and is deployed in heroku using docker container.
https://chapserver.herokuapp.com
Checkout the flutter client Chat app flutter
you have to run your postgres server at PORT 5432 then
npm install
npm start
first install docker and docker-compose
docker-compose up
in the project directory. then open http://localhost:3350 in your web browser