Fit yield curve models to observed Treasury and corporate bond yields. Access Nelson-Siegel, Svensson, and cubic spline interpolated curves with parameter estimates, fitted yields at any maturity, and forward rate extraction for fixed income analytics and derivatives pricing.
What shipped
- /v1/yield-curve/treasury — US Treasury fitted yield curve (any maturity)
- /v1/yield-curve/corporate/{rating} — corporate yield curves by credit quality
- Nelson-Siegel and Svensson model parameters with goodness-of-fit metrics
- Forward rate extraction and instantaneous forward rate curves
Endpoint
Primary path: /v1/yield-curve/treasury. Auth is a Bearer token. Responses are typed JSON documented in OpenAPI 3.0.3.
curl -H 'Authorization: Bearer YOUR_KEY' \
'https://api.eulerpool.com/v1/yield-curve/treasury'Authentication
Send Authorization: Bearer YOUR_KEY. Keys are created at register in under a minute. Official SDKs take the key in the constructor; Excel stores it in the add-in settings. There is no key-in-query-string mode — do not paste tokens into public notebooks.
Primary route for this article: /v1/yield-curve/treasury. Docs: /financial-data-api/fixed-income-data.
Coverage and freshness
Eulerpool maps 100,000+ securities across 90+ exchanges. yield curve modeling api API rides that same reference layer — identifiers resolve through ticker, name, ISIN, or CUSIP via search, so a European name is not a dead end. History depth depends on the source: prices and macro go back 100+ years, 1-minute bars to 2010, 13F to 2013.
Paid plans can stream quotes over WebSocket; the free plan uses REST with a 15-minute delay on real-time equity fields. Fundamentals, ownership, and calendars are identical on every plan. Rate-limit headers ship on every response. Batch routes (up to 100 symbols) count as one request.
Why it exists
Most teams land here after fighting Yahoo Finance scrapers, Alpha Vantage’s 25-request/day ceiling, or a Polygon bill that ignored fundamentals. Eulerpool is a licensed yield curve modeling api API with statements, estimates, filings, and macro on the same key — and a terms of service you can actually show legal.
Deep comparisons live here: vs Alpha Vantage, vs Polygon, Yahoo Finance alternative, best stock market APIs in 2026.
Who uses it
- Quant research — pandas/R dataframes, point-in-time fields, 20+ years of history where the source publishes it.
- Fintech apps — watchlists, screeners, and portfolio views without relicensing Bloomberg for every customer.
- AI agents — typed JSON and a native MCP server so models stop inventing numbers for yield curve modeling api API.
- Spreadsheets — the Excel and Google Sheets add-in covers the same endpoints as REST.
Get started
Create a free key at eulerpool.com/developers/register — no credit card, 100,000 requests/month. Then read the yield curve modeling api API docs and ship.
Every day’s drop is listed on the Financial Data API changelog. Same data powers the Eulerpool terminal 500,000+ investors already use — the API is that database with a key in front of it.