A US Treasury yield curve API returns every tenor you need for 2s10s in one payload — not a single 10Y print. On Bonds-API that is GET https://bonds-api.com/api/v1/curve?country=US with query api_key (not Bearer). Optional date=YYYY-MM-DD. Docs also show country=TR as the path example; the published JSON fixture is the US curve.
Starter is $19/mo (1,000 requests) with a 7-day trial. This is not Fed Funds / SOFR (Interest Rates API). MCP: https://mcp.bonds-api.com (bonds-api.com/mcp 404s). Docs: bonds-api.com/docs (curve).
Request: latest US curve
curl "https://bonds-api.com/api/v1/curve?country=US&api_key=YOUR_API_KEY"
Response: official curve fixture (2026-04-14)
{
"success": true,
"data": {
"country": "US",
"date": "2026-04-14",
"curve": [
{"maturity": "3M", "yield": 4.30},
{"maturity": "6M", "yield": 4.22},
{"maturity": "2Y", "yield": 3.80},
{"maturity": "5Y", "yield": 4.05},
{"maturity": "10Y", "yield": 4.25},
{"maturity": "30Y", "yield": 4.55}
],
"spread_2y_10y": 45.0,
"inverted": false
},
"meta": {
"request_id": "3efeeaa7-d4ab-4cde-8104-78fd402052a9",
"timestamp": "2026-04-14T09:00:00Z"
}
}
spread_2y_10y is 45.0 basis points in this fixture (10Y minus 2Y, times 100). inverted is false. Copy the curl for a live print.
Nearby endpoints
GET /api/v1/latest?countries=US&maturities=10Y— one tenor.GET /api/v1/spread?country=IT&benchmark=DE&maturity=10Y— cross-country spread (not 2s10s).GET /api/v1/timeseries//intraday— history.
Go live
1. Register — 7-day trial.
2. Copy api_key.
3. GET /api/v1/curve?country=US.
4. Chart data.curve and store spread_2y_10y.
