Use HUD's apartment loan data from code or an AI agent

At a glance

MCP server

Point any MCP client at https://hudmultifamily.loan/mcp. It speaks the current MCP revision (2026-07-28, with server/discover) and the earlier initialize handshake (2025-11-25, 2025-06-18, 2025-03-26), answers in plain JSON and keeps no session. In Claude, add it as a custom connector with that URL. In Claude Code: claude mcp add --transport http endorsement-index https://hudmultifamily.loan/mcp. In a JSON config:

{
  "mcpServers": {
    "endorsement-index": {
      "type": "http",
      "url": "https://hudmultifamily.loan/mcp"
    }
  }
}

Every result has a readable text answer plus structuredContent with the as-of date, the source URL and a page to cite. Try it with curl:

curl -s https://hudmultifamily.loan/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"curl","version":"1"}}}'

curl -s https://hudmultifamily.loan/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/call' -H 'Mcp-Name: size_223f' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"size_223f",
       "arguments":{"noi":1450000,"value":21000000,"note_rate":5.5,"unit_mix":{"1":80,"2":60}},
       "_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28",
                "io.modelcontextprotocol/clientInfo":{"name":"curl","version":"1"},
                "io.modelcontextprotocol/clientCapabilities":{}}}}'

JSON API

Plain GET requests, JSON out, CORS open to any origin, cached for up to an hour. Every response names its asof date and source. Results page with limit and offset, and include a next link.

Examples:

# Low-rate 223(f) loans in Texas with 10+ years left, lowest rate first
curl -s 'https://hudmultifamily.loan/api/v1/loans?state=TX&program=223f&max_rate=4&min_years_left=10&sort=note_rate&limit=10'

# One loan: Castle Square Apartments, Boston, MA
curl -s https://hudmultifamily.loan/api/v1/loans/02311561

# 2026 statutory limit for 80 one-bedroom and 60 two-bedroom elevator units under 221(d)(4)
curl -s 'https://hudmultifamily.loan/api/v1/limits?program=221d4&elevator=true&unit_mix=%7B%221%22%3A80%2C%222%22%3A60%7D'

// In a browser or Node 18+
const r = await fetch('https://hudmultifamily.loan/api/v1/loans?state=FL&max_rate=3.5&limit=5');
const { asof, total, results } = await r.json();

Downloads and Markdown

If you need the whole file, take the CSV or JSON on About the data rather than paging the API: one row per loan, every HUD field plus the street address, with a column dictionary. Program and guide pages have Markdown twins at the same path plus .md (the home page is /index.md), with the answer, key facts, sources and FAQ in a header block. They are marked noindex so they never compete with the pages themselves.

What the data is, and is not

• Loan figures are HUD's, from its active insured multifamily mortgage file, apartment loans only. Section 232 health care, hospitals and single-family FHA are not covered.
• Note rates are each loan's own historical rate, excluding MIP. The "benchmark" is the median rate on loans HUD endorsed in the prior 12 months. Neither is a quote.
• Program rules cite HUD Mortgagee Letters, the Federal Register, the U.S. Code and the 2020 MAP Guide, with dates. The ROAD to Housing Act limits are reported as enacted but pending HUD implementation and are never used in a calculation.
• Sizing tools are estimates from published rules, not underwriting and not an offer of credit.

License and citation

HUD's loan data is a U.S. government work in the public domain. Our compilation, derived figures and text are licensed CC BY 4.0. Please cite:

Endorsement Index (hudmultifamily.loan), from HUD's active insured multifamily mortgage file, as of 2026-09-30. https://hudmultifamily.loan/

Fair use: cache what you fetch and keep request rates modest; bulk users should use the downloads. Questions or a heavier use case: hello@hudmultifamily.loan.

Endorsement Index is published by Janover Capital LLC, a commercial mortgage advisor, not a lender. It is not affiliated with or endorsed by HUD, FHA or any government agency.