keystone · runs in your browserThe stack, wired
Sign in, pick a tenant, meter some usage, then ask the member about the bill. Identity gates it, tenancy isolates it, billing prices it to the exact minor unit and posts a balanced ledger, and the member reads the same state. The four kits over one executor. It is a faithful simulation; nothing here touches a database.
identity-kit
tenant-kit
billing-kit
ai-memberNo events yet: meter one to see the ledger post.
Scoped to acme. globex owes $0.00. A separate ledger you can’t see from here.
Four moves, one per kit
The fire button gates the moment the session drops. Identity is not a login form on the side. Every other kit refuses to move without a subject.
Meter usage as Acme, flip to Globex, and watch the invoice, usage counters and ledger swap wholesale. Two tenants, one tab, zero bleed.
Replay sends the same idempotency key again. The duplicate is caught, shown dashed in the ledger, and the total does not move: exact Money, balanced postings, no double charge.
The member answers from the same tenant-scoped state the ledger shows: grounded in what actually posted, not a summary that can drift from the money.
This wiring ships as a real app
keystone is the same four kits composed into a CRM you can run today. Open-source core, managed Cloud, native mobile.