Overview

Subscriptions allow GraphQL clients to observe specific events and receive updates from the server when those events occur. This supports live updates, such as websocket pushes. Subscriptions introduce several new concepts:

• The Subscription type is the entry point for subscription queries
• Triggers begin the update process
• The Implementation provides application-specific methods for executing & delivering updates.

Subscription Type

subscription is an entry point to your GraphQL schema, like query or mutation. It is defined by your SubscriptionType, a root-level GraphQL::Schema::Object.

Read more in the Subscription Type guide.

Triggers

After an event occurs in our application, triggers begin the update process by sending a name and payload to GraphQL.

Read more in the Triggers guide.

Implementation

Besides the GraphQL component, your application must provide some subscription-related plumbing, for example:

• state management: How does your application keep track of who is subscribed to what?
• transport: How does your application deliver payloads to clients?
• queueing: How does your application distribute the work of re-running subscription queries?

Read more in the Implementation guide or check out the ActionCable implementation or Pusher implementation.