Exact date arithmetic — the calendar math LLMs guess at

Exact date arithmetic — the calendar math LLMs guess at. ?from=&to= → days, business days, weeks, hours between; ?date=&add=30d|2w|3m|1y|10bd → the resulting date (bd = business days); ?date= alone → weekday, ISO week, day-of-year, leap year, unix. All UTC, Mon-Fri business days, real-calendar validation (Feb 30 is rejected).

Price: $0.001 per call, paid in USDC via the x402 protocol (see the x402 security scheme).