Concepts

Channels

A channel is a named stream of events within an App. Clients subscribe to channels to receive events. Channels are lightweight — you can create as many as your product needs.

Routing

Routing rules determine which events are sent to which channels and recipients. Rules are defined in the dashboard or via the API and evaluated on every ingest call.

Rules can filter by:

• Event type (order.shipped, user.mentioned, etc.)
• Payload fields
• Recipient attributes

Transforms

A transform modifies an event’s payload before delivery. Common uses:

• Schema mapping — rename fields to match what clients expect.
• Enrichment — add fields from an external lookup.
• Redaction — strip fields that should not reach the client.

Transforms are applied in order, per channel.

Delivery

SSE delivers events to connected clients over WebSocket. Delivery semantics:

• At-least-once — events are retried until acknowledged.
• Ordered per channel — events arrive in the order they were ingested.
• Fanout — one ingest call can deliver to many subscribers simultaneously.