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Send Your First Metric

This guide picks up after the Quickstart. You’ll learn batching, tags, and events — the three features you’ll use most after the initial “hello world.”

Prerequisites

  • A Plexus account with an API key
  • Python 3.10+ and plexus-python installed (see Quickstart)

Step 1 — Send a batch

Batching multiple metrics in one request reduces network overhead, which matters on constrained hardware:

from plexus import Plexus
 
px = Plexus(api_key="YOUR_API_KEY", source_id="robot-01")
 
px.send_batch([
    ("battery.voltage",      12.4),
    ("battery.current_ma",   340),
    ("sensor.temperature_c", 23.5),
    ("sensor.humidity_pct",  54.1),
    ("motor.rpm",            1200),
])

Metric naming convention: <subsystem>.<metric> — e.g. battery.voltage, motor.rpm, sensor.temperature_c. Consistent naming makes dashboard queries and alerts easier to build.

Step 2 — Verify

curl https://api.plexus.company/v1/sources/robot-01/metrics/latest \
  -H "x-api-key: YOUR_API_KEY"
{
  "metrics": {
    "battery.voltage":      12.4,
    "battery.current_ma":   340,
    "sensor.temperature_c": 23.5,
    "sensor.humidity_pct":  54.1,
    "motor.rpm":            1200
  }
}

Step 3 — Add tags

Tags let you slice data by firmware version, location, or any dimension:

px.send("sensor.temperature_c", 23.5, tags={
    "location": "warehouse-a",
    "firmware": "1.4.2",
})

Tags are indexed and queryable — keep them low-cardinality (not UUIDs or timestamps).

Step 4 — Send events

For state changes, faults, or any non-numeric data, use data_class="event":

px.send("motor.state_change", {"from": "IDLE", "to": "RUNNING"}, data_class="event")
px.send("device.fault", {"code": "E_MOTOR_STALL", "sensor": "encoder"}, data_class="event")

Events appear in the Logs endpoint, separate from numeric metrics.

Next steps

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