REST API

Mortgage Rates API

Access real-time and historical U.S. mortgage rate data from the Freddie Mac PMMS survey. 30-year fixed, 15-year fixed, and 5/1 ARM—updated weekly, delivered as JSON.

6Endpoints

50+Years of Data

3Loan Types

How It Works

Mortgage rate data in three steps

Create an API Key

Make API Requests

Send GET requests with your API key in the X-API-Key header. All responses return JSON.

Build Your App

Integrate mortgage rate data into your fintech app, dashboard, or analysis pipeline.

Quick Example

Get current rates in one call

A single request returns the latest rates for all mortgage types with week-over-week and year-over-year changes.

Request

curl -X GET "https://api.lambdafinance.io/v1/api/mortgage-rates" \
  -H "X-API-Key: YOUR_API_KEY"

Response

{
  "status": "success",
  "data": [
    {
      "rate_type": "30Y_FIXED",
      "rate": 6.65,
      "wow_change": -0.04,
      "yoy_change": -0.24,
      "survey_date": "2026-02-06"
    },
    {
      "rate_type": "15Y_FIXED",
      "rate": 5.89,
      "wow_change": -0.02,
      "yoy_change": -0.31,
      "survey_date": "2026-02-06"
    },
    {
      "rate_type": "5_1_ARM",
      "rate": 6.12,
      "wow_change": 0.01,
      "yoy_change": -0.18,
      "survey_date": "2026-02-06"
    }
  ]
}

API Endpoints

6 endpoints for mortgage rate analysis

Current rates, historical data, comparisons, spreads, and statistical summaries—all from a single base URL.

GET /api/mortgage-rates Live Rates

Current weekly rates for 30-year fixed, 15-year fixed, and 5/1 ARM from the Freddie Mac PMMS survey.

GET /api/mortgage-rates/{rate_type} Live Rates

Latest rate for a specific mortgage type with week-over-week and year-over-year changes.

GET /api/mortgage-rates/history Historical

Historical mortgage rate data with configurable date ranges and rate type filtering.

GET /api/mortgage-rates/compare Analysis

Side-by-side comparison of all mortgage types with spread analysis and trend direction.

GET /api/mortgage-rates/spreads Analysis

Rate spreads between mortgage types, including 30Y-15Y and 30Y-ARM differentials.

GET /api/mortgage-rates/statistics/{rate_type} Analysis

Statistical summary including min, max, mean, median, and percentile rankings for any rate type.

Data Source

Trusted, institutional-grade data

Freddie Mac PMMS

Data sourced from the Primary Mortgage Market Survey, the most widely referenced benchmark for U.S. mortgage rates since 1971.

Weekly Updates

New rate data published every Thursday and automatically ingested into our system. Background monitors ensure data stays current.

FRED API Backed

Delivered through the Federal Reserve Bank of St. Louis FRED database, ensuring reliability and accuracy for financial applications.

Pricing

Start free. Scale when you need to.

Free

$0/month

Perfect for prototyping and personal projects

50 requests per month
All mortgage rate endpoints
50+ years of historical data
No credit card required

Frequently asked questions

Ready to integrate mortgage rate data?

Get your free API key and start pulling live rates in under a minute.