ParkTandem

In a tandem parking lot the spaces sit in a row. If yours is at the back and the car in front is parked, you are not leaving. Today that gets solved with a WhatsApp group, shouting down a hallway, or a phone number left on a windshield.

ParkTandem turns it into something that works. Everyone checks in with one tap when they park. The app knows which spaces block which, and follows the chain all the way through. When someone needs to leave, it identifies who is blocking them right now and drafts the message with that person's name.

Each building or office is a location with a six character invite code, so neighbors join without an administrator setting up accounts one by one.