A Quick-Errand Childcare Swap for Parents

The idea

Sometimes I just need someone to watch my kid for an hour while I run to the pharmacy or the bank, but daycare won't take drop-ins and sitters have a three-hour minimum. I want a small neighborhood co-op where parents trade short blocks of childcare using simple credits instead of cash, so an hour I give now earns me an hour later. It only works within a few streets so pickups are quick and people actually know each other.