This is a Hackernews clone site built with next.js implementing GraphQL APIs, for which Apollo Client is adopted in the frontend and GraphQL Yoga in the backend server.
Subscriptions are a GraphQL feature that allows a server to send data to its clients when a specific event happens. Subscriptions are usually implemented with WebSockets or Server-Sent Events. GraphQL Yoga uses Server-Sent Events for the subscription protocol.
The real-time communication of subscriptions however was found not to function well once the package is deployed to Vercel, which is a serverless platform. We will not deploy this package to Vercel, however, a dockerized package of this app is prepared.
