{"service":"us-policy-rate","note":"Preview response with example params. Paid endpoint: POST /api/data/us-policy-rate","exampleParams":{"region":"National"},"sample":{"region":"National","target_lower_rate":3.5,"target_upper_rate":3.75,"effective_rate":3.63,"unit":"percent","period":"2026-09-06","source":"federal-reserve:fred"}}