Real-Time IORB (FED_IORB) Rate - InterestRatesAPI Blog

You need a reliable way to pull the Federal Reserve’s Interest on Reserve Balances (IORB) into your software, with exact effective dates, daily history, and ready-to-use stats. By the end of this guide, you’ll query FED_IORB in real time, retrieve historical and time series data, compute fluctuations and OHLC, and plug the rate into loan or spread calculations—all using the Interest Rates API over simple GET requests with api_key authentication.

What FED_IORB Represents and Why It Matters

FED_IORB is the Interest on Reserve Balances, set by the Federal Reserve for depository institutions’ balances at the Fed. It is a central bank policy rate in USD and acts as a key floor in the short-term interest rate corridor. For fintech developers and analysts, the IORB is useful to:

Illustration: Real-Time IORB (FED_IORB) Rate

Anchor pricing models for USD overnight rates and spreads against interbank benchmarks like SOFR.
Build macro dashboards and policy trackers alongside the federal funds rate and discount rate.
Benchmark treasury cash management and liquidity analytics.

In the Interest Rates API, the FED_IORB symbol is a daily-frequency central bank rate with values expressed in percent per annum. Dates are provided as YYYY-MM-DD effective dates.

Data Model, Units, and Effective Dates

Key points when working with FED_IORB via the API:

Units: The numeric value is a percentage rate per annum (e.g., 3.90 means 3.90% p.a.).
Frequency: Daily. Expect updates only on applicable business days; weekends and US holidays typically do not have new values.
Effective date: The API returns an effective YYYY-MM-DD in date fields (e.g., dates map), which you should treat as the calendar date on which the rate applies.
Currencies: For FED_IORB, currency_code is USD. Responses include a currencies map by symbol.
Caching: Cache latest responses briefly (e.g., minutes) and historical/time series responses longer (e.g., hours) unless your application needs near-real-time updates for policy-day changes.

You can learn more about the service at https://interestratesapi.com and explore model-capability patterns at the MCP.

Get the Latest FED_IORB (Real-Time)

The latest endpoint returns the most recent IORB value along with the effective date, currency, and a rates map keyed by symbol.

cURL (official sample; copy-paste ready)

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

JSON response (official sample; do not modify)

{
    "success": true,
    "date": "2026-10-22",
    "base": "USD",
    "rates": {
        "FED_IORB": 3.9
    },
    "dates": {
        "FED_IORB": "2026-10-22"
    },
    "currencies": {
        "FED_IORB": "USD"
    },
    "base_filter_note": null
}

How to read this:

rates.FED_IORB is the current IORB in percent per annum.
dates.FED_IORB is the effective date for that value.
currencies.FED_IORB confirms the currency (USD).
date at the top-level is the batch date of the response payload, which typically matches the effective date for daily symbols.

Python (requests)

import requests

resp = requests.get(
'https://interestratesapi.com/api/v1/latest',
params=dict(symbols='FED_IORB', api_key='YOUR_API_KEY')
)
data = resp.json()
iorb = data['rates']['FED_IORB'] # percent p.a.
iorb_date = data['dates']['FED_IORB'] # 'YYYY-MM-DD'
currency = data['currencies']['FED_IORB'] # 'USD'
print(iorb, iorb_date, currency)

JavaScript (fetch)

const response = await fetch(
'https://interestratesapi.com/api/v1/latest?symbols=FED_IORB&api_key=YOUR_API_KEY'
);
const data = await response.json();
const iorb = data.rates.FED_IORB; // percent p.a.
const iorbDate = data.dates.FED_IORB; // 'YYYY-MM-DD'
const currency = data.currencies.FED_IORB; // 'USD'
console.log(iorb, iorbDate, currency);

PHP

<?php
$url = 'https://interestratesapi.com/api/v1/latest?symbols=FED_IORB&api_key=YOUR_API_KEY';
$json = file_get_contents($url);
$data = json_decode($json, true);
$iorb = $data['rates']['FED_IORB'];
$iorbDate = $data['dates']['FED_IORB'];
$currency = $data['currencies']['FED_IORB'];
echo $iorb . " on " . $iorbDate . " " . $currency;

Discover Symbols with /symbols

Use the symbols catalogue to discover central bank rates (including FED_IORB) filtered by currency or category.

cURL

JSON response example

Note: The catalogue is filterable and will include multiple USD policy symbols. Look for the FED_IORB entry to confirm its attributes (category central_bank, currency USD, frequency daily).

Python

import requests
r = requests.get(
'https://interestratesapi.com/api/v1/symbols',
params=dict(category='central_bank', base='USD', api_key='YOUR_KEY')
)
symbols = r.json()['symbols']

JavaScript

const r = await fetch('https://interestratesapi.com/api/v1/symbols?category=central_bank&base=USD&api_key=YOUR_KEY');
const symbols = (await r.json()).symbols;

PHP

<?php
$url = 'https://interestratesapi.com/api/v1/symbols?category=central_bank&base=USD&api_key=YOUR_KEY';
$symbols = json_decode(file_get_contents($url), true)['symbols'];

Get a Value on a Specific Date with /historical

Fetch the FED_IORB value for a given date. For daily symbols, the API returns data for that date if available; otherwise you may get a 404 if the date is outside the available range.

cURL

JSON response example

Python

import requests
r = requests.get(
'https://interestratesapi.com/api/v1/historical',
params=dict(date='2025-06-15', symbols='FED_IORB', api_key='YOUR_KEY')
)
data = r.json()
iorb = data['rates']['FED_IORB']

JavaScript

const r = await fetch('https://interestratesapi.com/api/v1/historical?date=2025-06-15&symbols=FED_IORB&api_key=YOUR_KEY');
const data = await r.json();
const iorb = data.rates.FED_IORB;

PHP

<?php
$url = 'https://interestratesapi.com/api/v1/historical?date=2025-06-15&symbols=FED_IORB&api_key=YOUR_KEY';
$data = json_decode(file_get_contents($url), true);
$iorb = $data['rates']['FED_IORB'];

Pull a Time Series with /timeseries

Retrieve daily FED_IORB values between two dates, including frequency and currency metadata.

cURL

JSON response example

Read the rates.FED_IORB object as a date-to-value map. Use frequencies and currencies maps to confirm symbol attributes.

Python

import requests
r = requests.get(
'https://interestratesapi.com/api/v1/timeseries',
params=dict(start='2025-10-23', end='2026-10-23', symbols='FED_IORB', api_key='YOUR_KEY')
)
series = r.json()['rates']['FED_IORB'] # dict of 'YYYY-MM-DD' -> percent

JavaScript

const r = await fetch('https://interestratesapi.com/api/v1/timeseries?start=2025-10-23&end=2026-10-23&symbols=FED_IORB&api_key=YOUR_KEY');
const data = await r.json();
const series = data.rates.FED_IORB; // { 'YYYY-MM-DD': number }

PHP

<?php
$url = 'https://interestratesapi.com/api/v1/timeseries?start=2025-10-23&end=2026-10-23&symbols=FED_IORB&api_key=YOUR_KEY';
$data = json_decode(file_get_contents($url), true);
$series = $data['rates']['FED_IORB'];

Summarize Changes with /fluctuation

Use fluctuation to compute change, percentage change, and range (high/low) over any window. This is convenient for dashboards and alerting.

cURL

JSON response example

Key fields:

start_value and end_value are the first and last effective values in the window.
change and change_pct summarize the net move.
high and low are extrema over the period.

Python

import requests
r = requests.get(
'https://interestratesapi.com/api/v1/fluctuation',
params=dict(start='2025-10-23', end='2026-10-23', symbols='FED_IORB', api_key='YOUR_KEY')
)
stats = r.json()['rates']['FED_IORB']

JavaScript

const r = await fetch('https://interestratesapi.com/api/v1/fluctuation?start=2025-10-23&end=2026-10-23&symbols=FED_IORB&api_key=YOUR_KEY');
const stats = (await r.json()).rates.FED_IORB;

PHP

<?php
$url = 'https://interestratesapi.com/api/v1/fluctuation?start=2025-10-23&end=2026-10-23&symbols=FED_IORB&api_key=YOUR_KEY';
$stats = json_decode(file_get_contents($url), true)['rates']['FED_IORB'];

Build Candlesticks with /ohlc

The OHLC endpoint aggregates daily values into candlesticks for weekly, monthly, or quarterly periods—useful for visual summaries and pattern detection (e.g., policy cycles).

cURL

JSON response example

Each item contains open/high/low/close for the period plus data_points showing how many daily observations formed the candle.

Python

import requests
r = requests.get(
'https://interestratesapi.com/api/v1/ohlc',
params=dict(symbols='FED_IORB', period='monthly', start='2025-10-23', end='2026-10-23', api_key='YOUR_KEY')
)
ohlc = r.json()['rates']['FED_IORB']

JavaScript

const r = await fetch('https://interestratesapi.com/api/v1/ohlc?symbols=FED_IORB&period=monthly&start=2025-10-23&end=2026-10-23&api_key=YOUR_KEY');
const ohlc = (await r.json()).rates.FED_IORB;

PHP

<?php
$url = 'https://interestratesapi.com/api/v1/ohlc?symbols=FED_IORB&period=monthly&start=2025-10-23&end=2026-10-23&api_key=YOUR_KEY';
$ohlc = json_decode(file_get_contents($url), true)['rates']['FED_IORB'];

Compare Loan Costs with /convert

For quick “what if” comparisons, the convert endpoint estimates total interest for a simple loan priced at the latest rate of two symbols. Use it to compare, for example, a policy rate versus an interbank benchmark for a given principal and term.

cURL

JSON response example

The response includes the implied rate_spread and interest_saved for the amount and term at the latest rates of each symbol.

Python

import requests
r = requests.get(
'https://interestratesapi.com/api/v1/convert',
params=dict(from='FED_IORB', to='ECB_MRO', amount=100000, term_months=12, api_key='YOUR_KEY')
)
comparison = r.json()

JavaScript

const url = 'https://interestratesapi.com/api/v1/convert?from=FED_IORB&to=ECB_MRO&amount=100000&term_months=12&api_key=YOUR_KEY';
const comparison = await (await fetch(url)).json();

PHP

<?php
$url = 'https://interestratesapi.com/api/v1/convert?from=FED_IORB&to=ECB_MRO&amount=100000&term_months=12&api_key=YOUR_KEY';
$comparison = json_decode(file_get_contents($url), true);

Practical Usage: Spreads, Monthly Payments, and Dashboards

Here are common patterns you can adopt with FED_IORB data:

Policy dashboard: Use /latest for live tiles and /fluctuation for YTD or MTD change. The rates, dates, and change_pct fields give you quick badges and trend arrows.
Alerts: Subscribe your app logic to /latest. When the effective date advances and the rate differs from the previous close, trigger notifications.
Spread tracking: Compute spreads in your app using the latest endpoint. Example (conceptual):
- Fetch SOFR and FED_IORB via /latest?symbols=SOFR,FED_IORB
- spread = sofr - iorb, in percentage points.
Monthly payment estimation:
- Convert an annual percent to a monthly rate: r_month = iorb / 100 / 12.
- For an amortizing loan with principal P and term n months, the standard payment formula is:
  payment = P * r_month / (1 - (1 + r_month)^(-n)).
- For interest-only estimates, monthly interest = P * r_month.

When you need to show summarized behavior over months or quarters, prefer /ohlc so you can render candlesticks without pre-aggregating the daily series yourself. For simple year-over-year deltas or policy-window stats, /fluctuation removes manual calculations.

Operational Considerations

To make integrations reliable and cost-effective, consider the following:

HTTP method and auth: All endpoints are GET only. Authentication uses an api_key query parameter. Do not send keys in headers.
Business days: FED_IORB is daily. On weekends and US holidays, expect no new effective value; the latest call may continue to show the last business day’s date.
Caching:
- /latest: cache for a short TTL (e.g., minutes) while polling more frequently only on scheduled policy days if needed.
- /historical, /timeseries, /ohlc: cache aggressively; the historical record does not change retroactively for central bank benchmarks.
Error handling:
- 401/403: Check that api_key is present and valid.
- 404: No symbols matched or no data for the requested date/range; a details field may describe available ranges.
- 422: Validation error (e.g., date format not Y-m-d, invalid symbol).
- 429: Quota exhausted; respect Retry-After and check X-RateLimit-* headers.
Pagination: Not applicable; endpoints return the requested span. For large spans, plan for efficient JSON processing.
Time zone: Dates are YYYY-MM-DD effective dates; treat them as calendar dates for business logic rather than exact timestamps.

Bookmark the documentation hub at interestratesapi.com and the MCP for model capability patterns.

Endpoint Reference: FED_IORB Quick Index

/api/v1/symbols — Find FED_IORB and confirm currency/frequency.
/api/v1/latest — Get the most recent FED_IORB with effective date.
/api/v1/historical — Retrieve FED_IORB on a specific date.
/api/v1/timeseries — Pull daily FED_IORB values over any date span.
/api/v1/fluctuation — Summarize net change, percent change, high/low.
/api/v1/ohlc — Aggregate daily FED_IORB into weekly/monthly/quarterly candles.
/api/v1/convert — Compare loan interest costs using FED_IORB versus another symbol.

FAQ

Q: Are the FED_IORB values percentages or decimals?
A: Percentages per annum. For example, 3.9 means 3.90% p.a. Convert to a decimal as rate_pct / 100 when needed.

Q: How should I interpret the dates map versus the top-level date?
A: For multi-symbol queries, the top-level date is the payload date; the dates map gives each symbol’s effective date. Use dates.FED_IORB for symbol-specific logic.

Q: What happens on weekends or US holidays?
A: FED_IORB is daily. On non-business days there is typically no new value; /latest will show the last effective date until the next update.

Q: Can I compute MoM or QoQ moves without downloading raw daily data?
A: Yes. Use /fluctuation for change metrics over any window, or /ohlc to get monthly or quarterly open/high/low/close without manual aggregation.

Q: How do I compare FED_IORB to another benchmark for a simple loan?
A: Use /convert with from=FED_IORB and to=OTHER_SYMBOL. The response includes total_interest, total_payment, and rate_spread for your amount and term.

Ship your integration now with real-time FED_IORB and complete historical coverage. Register to get your API key, explore the MCP, and start building against interestratesapi.com with simple GET calls.

What FED_IORB Represents and Why It Matters

Data Model, Units, and Effective Dates

Get the Latest FED_IORB (Real-Time)

cURL (official sample; copy-paste ready)

JSON response (official sample; do not modify)

Python (requests)

JavaScript (fetch)

PHP

Discover Symbols with /symbols

cURL

JSON response example

Python

JavaScript

PHP

Get a Value on a Specific Date with /historical

cURL

JSON response example

Python

JavaScript

PHP

Pull a Time Series with /timeseries

cURL

JSON response example

Python

JavaScript

PHP

Summarize Changes with /fluctuation

cURL

JSON response example

Python

JavaScript

PHP

Build Candlesticks with /ohlc

cURL

JSON response example

Python

JavaScript

PHP

Compare Loan Costs with /convert

cURL

JSON response example

Python

JavaScript

PHP

Practical Usage: Spreads, Monthly Payments, and Dashboards

Operational Considerations

Endpoint Reference: FED_IORB Quick Index

FAQ

Ready to get started?