Buying together with a neighbor.
Warehouse packages often cost less but are too large for one household. Two neighbors can split a case, take turns driving, and divide the cost. Their archives handle reminders, matching, and calculations without revealing either person's shopping history. The technical page explains the protocol.
The idea, in one picture
Two houses, two archives, and envelopes between them. Neither archive ever opens the other. Each family keeps its own record of what was agreed, the way neighbors always have.
Your archive already holds your receipts. Reading them at home, it learns your rhythm (olive oil about once a month, paper towels every couple of months) and keeps a quiet shopping list. When something on that list comes in a big cheap case, it can ask, with your say-so: does a neighbor want to split one?
The story, with made-up people
Carmen's archive knows she buys olive oil about every four weeks (that knowledge never leaves her house). Her neighbor Jodie's archive knows the same about hers. Both say yes to asking. The asks meet, the two agree (Jodie shops Saturday, they split a case of six), and afterward the math comes back to the penny:
olive oil 2L × 6 41.94
tax 3.36
her 3 bottles 22.65
paid neighbor-to-neighbor,
cash or Venmo.
Money never moves through us.
Only the lines they agreed to share came off Jodie's receipt. Whatever else she bought that day is nobody's business. The envelope has room for the agreed lines alone, so the system can't send the rest even by mistake.
And Carmen's archive, knowing what she used to pay for the small bottle, tells her plainly: this run saved you $35.25. If it doesn't know your old price, it says “unknown,” because it never invents savings.
The six steps
Your archive reads your own receipts, at home. It learns what you buy regularly and what you usually pay. Nothing is sent anywhere. This is your house reading your papers.
It proposes; you approve. “These eight things come in splittable cases — want to ask the neighbors?” Nothing is shared until you say yes, item by item.
The ask travels, and only the ask. “Olive oil, this size, within two weeks, near me.” It carries none of your history, your prices, or your brands. And only to neighbors you already know and chose: your circle.
You agree on the run. Who shops, how it splits, a price cap, what substitutes are okay. Both archives keep the same agreement, initialed by both.
The shopper shops; the math comes back exact. Only the shared lines of the receipt cross. The split (tax included) works out to the penny, and the money itself changes hands the way it always has between neighbors: cash, Venmo, Zelle. The system does arithmetic. It never touches money.
Porch handoff, and each archive writes its own record. You split sealed bottles at the shrink-wrap, so nobody has to repackage anything. Cold things go home the same day. Your archive quietly totals what buying together saved you this month.
What never leaves your house
Your shopping history. What you buy says a lot about a person: health, faith, household, budget. It stays home, the same as your bloodwork.
What you used to pay, and how often you buy. The archive uses these to spot good splits and count your savings — locally.
Every other line on the shopper's receipt. Only the agreed items cross, ever.
The why. If your archive suggested splitting olive oil because your own records say you cook more now, the neighbor never hears the reason. She gets a plain ask.
One privacy limit: paying a neighbor through Venmo puts your name on their phone, outside anything KISOP controls. Cash is the only fully private settlement method.
Who this is for
Anyone whose budget is squeezed, which is most of us. But it was drawn first for the person on a fixed income who can't drive to the warehouse store and could never use thirty rolls of paper towels alone. Split four ways among neighbors, with one driver, the warehouse price finally belongs to her too. Buying together is the oldest neighborhood economy there is; the archive just does the remembering, the matching, and the arithmetic, and keeps everyone's privacy while it does.
Neighbors you know first
Today this works within a circle you choose (people who already trust each other). Matching with neighbors you haven't met yet is designed (carefully, so nobody can fish for what you buy). The build has not started. We'll say so here when that changes.
The archive pays for itself
If splitting bulk runs saves a household $40–80 a month, the archive is the thing that found the savings. That's the economy underneath, made concrete on one receipt.
Where this stands
Built July 9, 2026, as a working prototype, on invented data. Two made-up archives on one computer ran the whole exchange, watched by 143 automated checks. No one's real records were involved, including the founder's.
There is no product to download yet. The pieces ship in the open, in order, and this page will say so, dates and all, when that changes.
Two things are with the lawyers: warehouse-club membership rules (one member shopping, neighbors reimbursing; we ask counsel before any pilot), and how food-safety norms are written into the community guidelines.
How to help, and how to tell us something's wrong
See a problem, or something that worries you? On the main site: Write to us → “feedback,” or Write to us → “security” for good-faith lock-testing: welcomed, credited, promised in the Terms.
Want to build it with us? Apply → “build,” and read the technical page — it shows exactly what exists, what the tests enforce, and what has yet to be built.
Just following along? The “New in this place” board on the home page announces every change, dated.