Glossary
Presence (online status)
Presence is the real-time indication of a user’s availability or connectivity state in a messaging system, typically expressed as online, offline, away, busy or a custom status.
General definition
Presence is one of the foundational signals in any real-time communication system. When a user opens a chat application, their client announces its connected state to the server. The server distributes that state to the user’s contact list or channel members, so everyone can see who is available right now.
- Online: the user’s client is connected and the user is active
- Away / idle: connected but no recent input detected
- Do not disturb (DND) / busy: connected but explicitly suppressing notifications
- Offline: client is disconnected or presence subscription is absent
- Custom status: user-defined text or emoji (“In a meeting until 3pm”)
Presence subscriptions define who can see whose state. In XMPP the subscribe / subscribed stanza pair creates a mutual presence subscription; in proprietary systems the equivalent is a channel membership or friend relationship. Presence data is inherently ephemeral and changes frequently, so it is delivered over a persistent connection such as WebSocket rather than polled via REST.
At scale, presence is one of the more resource-intensive features to implement correctly. Each state change must fan out to potentially thousands of subscribers. High-performance systems batch and coalesce updates to avoid thundering-herd problems when many users come online simultaneously.
In the Ethora ecosystem
Ethora’s Chat SDK exposes presence as a first-class API. The SDK tracks connected state automatically and surfaces real-time online indicators in chat lists and conversation headers. Applications can also set custom availability statuses that sync across the user’s sessions.
In healthcare and financial-services deployments, presence plays a practical operational role: care teams need to know which colleagues are reachable before escalating a message. Self-hosted and dedicated Ethora instances keep all presence data within the customer’s own infrastructure, which matters for environments where user availability is considered sensitive information.
