Scollector is a monitoring agent that can be used to send metrics to Bosun or any system that accepts OpenTSDB style metrics. It is modelled after OpenTSDB's tcollector data collection framework but is written in Go and compiled into a single binary. One of the design goals is to auto-detect services so that metrics will be sent with minimal or no configuration needed. You also can create external collectors that generate metrics using a script or executable and use Scollector to queue and send the metrics to the server.
You are NOT required to use Scollector when using Bosun, as you can also send metrics directly to the /api/put route, use another monitoring agent, or use a different backend like Graphite, InfluxDB, or ElasticSearch.