Watch the car, not a refresh button

Streaming and polling are different mechanisms

A polling app holds your credentials and asks the car for its state on a timer. Between two of those reads it knows nothing, so it interpolates: a trip becomes a line between the points it happened to catch, and a charging curve becomes a guess. Poll often enough to fix that and you start keeping the car awake, which owners notice as overnight battery loss.

A streaming app registers a telemetry endpoint with Tesla and waits. The car decides when to send, so the app never initiates contact and never wakes anything. The cost is that you see what the car chooses to publish, and the benefit is that what you see is what the car actually reported, at the moment it reported it.

What arrives, and how often

Thirty-six fields, at intervals the car sets and we do not exaggerate. Speed, gear, charge state, charging power, location, Sentry state and the car's own alerts arrive while it is awake; when the car sleeps, the stream goes quiet, and the app says so rather than showing you a stale figure as though it were live.

Every field carries the time it was last heard. A value that is minutes old is labelled minutes old. This is the least glamorous decision in the product and the one we would defend hardest: an app that hides staleness is an app that quietly lies to you once a day.

What you need

A Tesla account, and a car that supports Fleet Telemetry. DashM8 asks your car to start streaming the moment you connect it and shows you exactly what the car answered — so you learn whether yours works on the free plan, before paying anything. A virtual key is needed only for commands, and it can wait.