US Treasury yield curve API: the latest Daily Treasury Par Yield Curve — yields in percent for 13 maturities from 1 mont

US Treasury yield curve API: the latest Daily Treasury Par Yield Curve — yields in percent for 13 maturities from 1 month to 30 years, plus curve date, straight from the US Department of the Treasury. Public-domain government data, published each business day. Use for interest rate benchmarks, bond analysis, discount rates, and macro signals. Slow upstream (~10s) so served from a 6-hour cache; meta.fetchedAt shows when the curve was retrieved.