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Semantik exposes six metrics that reflect live broker activity. They are delivered via a server-sent events stream and displayed on the Semantik dashboard.

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Metric definitions

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Sent

Messages successfully published to the Semantik broker.
WindowDescription
/secMessages published in the last second
/minMessages published in the last minute
/hrMessages published in the last hour

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Delivered

Messages matched by at least one active subscription and delivered to a subscriber.
WindowDescription
/secDeliveries in the last second
/minDeliveries in the last minute
/hrDeliveries in the last hour
A message is counted as delivered once per matching subscription. If two subscribers match the same message, it counts as two deliveries.

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Bandwidth

Total data transferred through the broker (publish + delivery payloads combined).
WindowDescription
/secBytes transferred in the last second
/minBytes transferred in the last minute
/hrBytes transferred in the last hour

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Errors

Failed publish or delivery operations.
WindowDescription
/secErrors in the last second
TodayErrors since midnight UTC
This weekErrors in the current calendar week
This monthErrors in the current calendar month

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Subscriptions

The number of active SemQL subscriptions registered with the broker at this moment. Each unique subscription query from a connected agent counts as one subscription.

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Subscribers

The number of agents currently connected to the broker. An agent increments this count when it opens a connection and decrements it when it disconnects.

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SSE stream

Metric data is delivered via server-sent events at GET /semantik/events. Authentication is required. The stream emits updates on each broker tick and closes after 120 seconds of inactivity — clients should reconnect automatically. The dashboard reconnects transparently; no manual action is needed.