Telemetry and attributes

Telemetry

Telemetry is a reading: temperature, voltage, a counter, a text value. When a device sends it, the platform stores it and updates the latest value. Dashboards, alarms, and rule chains then see that stored reading. A text value such as "hot" is stored and shown. A chart draws numbers. A key that is not a number stays as text on the device page and on a chart card.

A post that is stored returns success with stored: true. A post the plan does not store returns HTTP 429 with success: false. The Free plan stores at most one reading every 30 seconds. Hobby is 10 seconds, Starter is 5, and Growth and Enterprise are 1. The reading is not stored. The same refusal applies when the plan’s per-minute or per-day cap is full.

A batch body is {"items":[{"ts":1710000000000,"telemetry":{"pressure":150}}]}. accepted is the number of items stored. Each refused item has success: false. A field named ts on a batch item is the time of that reading. It is not stored as a key. The plan minimum interval is the gap between those reading times. Two past rows a minute apart are stored. A second row with the same time is refused. One HTTP post with two keys counts as two stored keys on Home.

The latest value of a key is the reading with the newest time. An older reading that arrives later stays in the history. It does not replace the latest value, and the chart still includes it.

You do not add a “save” step. If a rule chain is bound to the device’s profile and the chain reaches Drop, that reading is not stored. The reply says it was dropped. A profile alarm rule still runs on the reading the device sent. Any other end of the chain still stores it.

A chain can hold a reading while a delay runs, and the platform stores it when the delay finishes. That is still the platform saving the reading.

Attributes

An attribute is a value kept on the device, not a time series point.

• Client attributes are sent by the device. The platform stores them. A rule chain can see them when Message in accepts attributes.
• Server and shared attributes are written by the platform or by a person. Set attribute in a rule chain writes one of these. That node is for a value the chain decides. It is not required to keep what the device already sent.
• A shared attribute can be pushed to the device. A client attribute is the device reporting back.

Deleting an attribute removes that key. It does not delete telemetry history.