Free Mortgage Data Index API 2026 — Developer Documentation

Access our mortgage data index programmatically via our free REST API. No API key required.

Quick Start

Base URL: https://mortgagedataindex.com/wp-json/mortgagedata/v1/

Authentication: None required (public API)

Rate Limit: 60 requests per minute

Format: JSON

Endpoints

GET /mortgagedata/v1/rates

Get current mortgage rates by loan type and state

Parameters: type, state, credit

Example:

https://mortgagedataindex.com/wp-json/mortgagedata/v1/rates?type=30-year-fixed&state=california&credit=good

GET /mortgagedata/v1/calculate

Calculate monthly mortgage payment

Parameters: price, down, rate, term

Example:

https://mortgagedataindex.com/wp-json/mortgagedata/v1/calculate?price=500000&down=20&rate=7.0&term=30

GET /mortgagedata/v1/affordability

Calculate how much home you can afford

Parameters: income, debts, down, state

Example:

https://mortgagedataindex.com/wp-json/mortgagedata/v1/affordability?income=120000&debts=1500&down=60000&state=texas

GET /mortgagedata/v1/states

All states with current average mortgage rate

Parameters: none

Example:

https://mortgagedataindex.com/wp-json/mortgagedata/v1/states

Response Format

All endpoints return JSON with these common fields:

{
  "source": "https://mortgagedataindex.com",
  "last_updated": "2026-04-08",
  "disclaimer": "Data estimated from 2026 research."
}

Usage Terms

  • Free to use for personal and commercial projects
  • Attribution required — include a link to https://mortgagedataindex.com as your data source
  • No warranty — data is provided as-is for reference
  • Rate limit — please limit to 60 requests per minute

Need Help?

Questions about the API? Contact us.

API Version 1.0 | Last updated: April 2026