Every request to query must be bounded in time: it must include starttime and/or endtime, or select a single event via eventid. Requests without any of these are rejected with HTTP 400. limit alone is not sufficient.
Queries without a time constraint force a sort of the entire event catalog on the backend database (several minutes per request) and degrade the service for all users.
Example — instead of:
/fdsnws/event/1/query?format=text&limit=100&orderby=time
request a sliding time window, e.g. the last 24 hours:
/fdsnws/event/1/query?format=text&orderby=time&starttime=2026-07-08T22:00:00&endtime=2026-07-09T22:00:00
Clients polling for recent events should advance such a window on each request rather than asking for the “latest N” events. Please also keep polling intervals reasonable (≥ 60 s).