Performance & limits
Latency
Latency is the elapsed time between a chosen starting point and a resulting action, such as publishing an event and rendering it on a subscriber's screen.
Also found under: End-to-end delay, Round-trip time, RTT
How it works
Measurements mean different things depending on their boundaries. HTTP response time, network round-trip time and visible update delay are not interchangeable. Assess typical behavior and slower tail cases, because averages can hide poor experiences caused by weak networks or busy clients.
In a Pubb integration
Measure Pubb integrations across the full path: backend work, publication acceptance, event delivery and UI rendering. A fast acceptance response does not establish when all subscribers processed the event.
Connect a clientA practical example
Instrument a test event and its receiving handler, accounting for clock differences between machines. Separately measure how long the UI takes to render the update.