Rules

Rules derive facts from other facts and parameter services. They are the source-backed calculation steps behind calculator reports.

When this matters

You usually do not call rules directly as an API or SDK consumer. You need the model when you inspect graph metadata, review diagnostics or contribute tax behaviour.

How it works

txt
GrossPay
  -> taxable pay rule
  -> PAYG withholding rule
  -> net pay rule
  -> TakeHomePayReport

Rules have descriptors so TaxKit can expose graph edges, source references and required facts through metadata endpoints.

Parameters

Tax-year rates and thresholds are services. The same algorithm can be paired with different parameter layers for different effective periods.

Read this page as Markdown