Domains

A domain is a self-contained model of a calculation area. It bundles the variables you calculate with and the activities — the equations — that relate them. A domain is the unit you target when you run a calculation. A mortgage domain, for example, brings together variables like home price, down payment, interest rate, term, and monthly payment, along with the activities that connect them. A construction domain brings together material quantities, unit conversions, and cost projections. The domain changes from one area to the next; the way you work with it does not.

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What a domain contains

• Variables — the named values in the domain, each with a type, an optional default, and units. See Variables.
• Activities — the equations that define how variables relate. Depending on which values are known, an activity can solve for different variables. See Activities.

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Identity and versions

A domain is identified by a stable UUID — the domain_id you pass to the API — and carries a title and description. The description is written for both people and machines; clear, precise descriptions improve natural-language and agent results. The UUID is what you use to reference a domain. A domain also carries a stable key that TrueMath assigns when the domain is created. Where the UUID identifies a domain within the account it lives in, the key is how TrueMath recognizes the same domain across accounts: when you copy a domain to another account, the copy shares the source’s key but takes its own UUID, so copying it again later updates that copy in place rather than creating a duplicate. The key is assigned, not chosen, and it does not appear in a domain’s exported definition — an import overrides the domain you import it into, which you select; it is not matched by a key in the JSON. See Creating a domain. A domain moves through a version lifecycle: you edit a draft, then publish it. Calculations always run against the published version, and only published domains are available through the API and the Playground.

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Where domains come from

• The domain library — TrueMath ships pre-built, role-based domains across several professional verticals. See the Domain library.
• Your own domains — author a domain from scratch, or customize a library domain to match your conventions and business logic. See Authoring overview.