draft optional author:Semisol
Relays may decide to allow replaceable and/or ephemeral events.
A regular event is defined as an event with a kind 1000 <= n < 10000.
Upon a regular event being received, the relay SHOULD send it to all clients with a matching filter, and SHOULD store it. New events of the same kind do not affect previous events in any way.
A replaceable event is defined as an event with a kind 10000 <= n < 20000.
Upon a replaceable event with a newer timestamp than the currently known latest replaceable event with the same kind being received, and signed by the same key, the old event SHOULD be discarded and replaced with the newer event.
An ephemeral event is defined as an event with a kind 20000 <= n < 30000.
Upon an ephemeral event being received, the relay SHOULD send it to all clients with a matching filter, and MUST NOT store it.
Clients SHOULD use the supported_nips field to learn if a relay supports this NIP. Clients SHOULD NOT send ephemeral events to relays that do not support this NIP; they will most likely be persisted. Clients MAY send replaceable events to relays that may not support this NIP, and clients querying SHOULD be prepared for the relay to send multiple events and should use the latest one.
- States: An application may create a state event that is replaced every time a new state is set (such as statuses)
- Typing indicators: A chat application may use ephemeral events as a typing indicator.
- Messaging: Two pubkeys can message over nostr using ephemeral events.