Wallets
The container for everything you track: its base currency, who can reach it, and why most people need only one.
A wallet holds your assets, their transactions, and the categories, plans and scenarios built on top. It is the unit of sharing and the unit of scoping: every route in the API except one is /wallets/{walletId}/….
Base currency
Each wallet has one, set when you create it. It is the currency your net worth and every cross-currency total is expressed in.
Individual holdings keep their own currency. A portfolio in USD reports USD; only the totals convert, at the rate for the date being asked about rather than today's. So a historical net worth figure uses that day's rate and does not drift when the exchange rate moves.
Changing the base currency later is possible in wallet settings, and it re-expresses history rather than rewriting it.
One wallet or several
Most people want one. Everything you own in one place is the point: a net worth split across two wallets is not a net worth.
A second wallet makes sense when the money is genuinely separate and should never be summed — a company's books kept apart from your own, or a wallet you share with one person and not another. Sharing is per wallet, so separating is also how you give someone access to part of your picture without the rest.
Settings
Wallet settings cover the name, the base currency, the planning levels used by the planning view, and API keys. An owner can also delete the wallet, which deletes everything in it.
Sample wallets
A new account can start from a sample wallet, populated with realistic data so the reports have something to show before you have connected anything. It expires on its own. Nothing in it is yours, so do not build on it.