A US 5-year Treasury yield API returns one tenor, not the full curve. On Bonds-API the key is US_5Y. Call GET https://bonds-api.com/api/v1/latest?countries=US&maturities=5Y with query api_key (not Bearer). Official curve sibling dated 2026-04-14 prints 5Y 4.05.
Starter is $19/mo (1,000 requests) with a 7-day trial. This is not Fed Funds / SOFR. MCP: https://mcp.bonds-api.com. Docs: bonds-api.com/docs.
Request: latest 5Y
curl "https://bonds-api.com/api/v1/latest?countries=US&maturities=5Y&api_key=YOUR_API_KEY"
Do not invent a live US_5Y tick. The published numeric fixture is the US curve for 2026-04-14 (5Y row selected):
{
"success": true,
"data": {
"country": "US",
"date": "2026-04-14",
"curve": [
{"maturity": "2Y", "yield": 3.80},
{"maturity": "5Y", "yield": 4.05},
{"maturity": "10Y", "yield": 4.25}
],
"spread_2y_10y": 45.0,
"inverted": false
}
}
That envelope is GET /api/v1/curve?country=US. Latest returns {CC}_{TENOR} keys such as US_5Y. Copy the latest curl for today’s print.