Messaging basics
Fan-out
Fan-out is the distribution of one published event to multiple subscribers. It turns a single producer action into many outgoing delivery attempts.
Also found under: Broadcast, One-to-many delivery
How it works
A small publication can generate substantial traffic when its channel has many listeners. Estimate both the publishing rate and the number of recipients, then account for payload size. Splitting unrelated audiences into separate channels can reduce unnecessary deliveries without reducing useful updates.
In a Pubb integration
Pubb capacity includes publications and delivery attempts. A popular channel therefore consumes more operations and outgoing bandwidth than a channel with only a few subscribers at the same publishing rate.
Explore plans and capacityA practical example
An event sent to 100 connected subscribers creates up to 100 subscriber delivery attempts in addition to the publication itself. Ten such events per second multiply that work.