A SOFR rate API returns the secured overnight financing rate as JSON — not Fed Funds and not a 10-year yield. On Interest Rates API the symbol is SOFR. Call GET https://interestratesapi.com/api/v1/latest?symbols=SOFR with query api_key.
Starter is $19/mo (1 symbol per latest request, 250 calls, 90-day range) with a 7-day trial. Pro is $49 with multi-symbol latest. Do not pass base=USD when you also need SONIA or ECB prints. MCP: https://interestratesapi.com/mcp. Docs: interestratesapi.com/docs.
Request: latest SOFR
curl "https://interestratesapi.com/api/v1/latest?api_key=YOUR_API_KEY&symbols=SOFR"
Do not invent a live latest tick. The published numeric fixture is the convert sibling dated 2026-04-19:
{
"success": true,
"amount": 500000,
"term_months": 24,
"from": {
"symbol": "SOFR",
"rate": 4.31,
"date": "2026-04-19",
"total_interest": 43100.00,
"total_payment": 543100.00
}
}
That envelope is GET /api/v1/convert?from=SOFR&to=EURIBOR_3M&amount=500000&term_months=24. Latest returns the rate under rates.SOFR (same family as other symbols). Copy the latest curl for today’s print.
Go live
1. Register — 7-day trial.
2. Copy api_key.
3. GET latest with symbols=SOFR.
4. Persist date + rate.
