Blog

Notes on heat,
and building on Tesla's API

What actually heats a parked car, how Tesla's signed-command protocol works under the hood, and the incidents we've hit building VentMode on top of it.

Incident report·

We renamed our Tesla Fleet API app and it silently unregistered our domain

A first-hand incident report: changing the app display name in Tesla's developer portal dropped our partner registration, and the failure looked nothing like a naming problem — cars reported unpaired, commands failed with confusing errors.

Engineering·

What it actually takes to send a signed command to a Tesla

A from-the-implementation look at Tesla's Vehicle Command Protocol — the ECDH handshake, HMAC-SHA256 signing, and replay-protection counter that stand between an API call and your car's windows actually moving.

Comparison·

Cabin Overheat Protection vs. venting: the real trade-off Tesla doesn't spell out

Tesla's Cabin Overheat Protection runs the A/C while you're parked. Venting cracks the windows instead. Here's what each actually costs you in range and security, and when each one is the right call.

Explainer·

Why a parked Tesla turns into an oven — and why cracking the windows actually works

The greenhouse effect that heats a closed car cabin, why it happens faster in a Tesla's all-glass roof, and why venting a few inches of window beats almost everything else you can do about it.