Deterministic
Every payload names the algorithm version, configuration, fiscal-year bounds, and content hash.
Retail dates without calendar debt
One date in. The right retail week out.
A versioned JSON API for 4-5-4, 4-4-5, and 5-4-4 calendars, 53-week years, and comparable prior-year dates.
Transparent by design
Explicit week 53
Choose whether week 53 clamps to prior-year week 52 or returns no comparable date.
Low-data
The API receives dates and calendar settings—not sales, customers, inventory, or ledger data.