Fed Funds Daily Rate API: DFF as JSON

A Fed Funds daily rate API returns the effective federal funds rate for a calendar day, not the FRED monthly average. On Interest Rates API the symbol is FED_FUNDS_DAILY (FRED series DFF). Call GET https://interestratesapi.com/api/v1/latest?symbols=FED_FUNDS_DAILY with query api_key.

FED_FUNDS (no suffix) is the monthly average, stored on the first of the month. Official historical docs print FED_FUNDS = 5.33 on stored date 2025-09-01 when querying 2025-09-15. Use FED_FUNDS_DAILY when you need a session print. Starter is $19/mo (1 symbol/request, 250 calls, 90-day range) with a 7-day trial. Do not pass base=USD if you also need SONIA or ECB. Docs: interestratesapi.com/docs.

Use cases

• Daily desk mark. Plot rates.FED_FUNDS_DAILY and dates.FED_FUNDS_DAILY — not the month-1 average.
• Vs SOFR. Same /convert path already documented for SOFR vs EURIBOR_3M.
• Policy vs effective. Keep FED_FUNDS monthly next to this daily series.

Request: daily symbol

curl "https://interestratesapi.com/api/v1/latest?api_key=YOUR_API_KEY&symbols=FED_FUNDS_DAILY"

Sibling envelope: official FED_FUNDS monthly sample

Docs publish this monthly print. FED_FUNDS_DAILY uses the same keys — copy the live daily value from your key; do not invent a DFF tick here.

{
"success": true,
"rates": {
"FED_FUNDS": 5.33
}
}

MCP: interestratesapi.com/mcp.

Go live

Read daily Fed Funds with an Interest Rates key →