GraphQL subscriptions provide real-time capabilities within the GraphQL paradigm. Clients subscribe to events receiving updates over WebSocket connections. The unified schema covers queries, mutations, and subscriptions.
Subscription Implementation
Define subscription types in your schema. Implement resolvers that return async iterators. Publish events when data changes. Handle connection lifecycle properly.
- Use WebSocket transport for persistent subscription connections
- Implement pub/sub for distributing events to subscribers
- Filter subscriptions to relevant updates for each client
- Handle reconnection gracefully on client side
- Consider scaling implications for high subscriber counts
Use Cases
Live dashboards subscribe to metric updates. Chat applications stream new messages. Collaborative editing broadcasts changes. Notifications push to connected clients immediately.