Real estate · Housing momentum

Market Momentum API

Ranks 1,000+ U.S. counties each month by housing-market momentum, using listing-flow leading indicators with a verifiable historical track record. It doesn't tell you which property to buy — it answers a narrower question: which county markets are showing enough momentum to be worth a closer look?

1,000+ counties Monthly rankings Listing-flow leading signal Derived analytics

Get API key on RapidAPI Try a request

What you can build

For real-estate investors, analysts, lenders, and operators deciding where to underwrite next.

County screening

Pull the ranked list, filter by state, region, or population, and shortlist counties for deeper underwriting before sales data catches up.

Dashboards & alerts

JSON responses suited to dashboards, spreadsheets, alerts, and research pipelines — compare momentum across regions or watch shifts over time.

Endpoints

Base URL https://momentum-api.remulouslabs.com — proxied for you by RapidAPI. /v1/openapi.json, /v1/meta, and /healthz are open (no key).

GET/v1/counties/ranked

Ranked list of counties by momentum score, in a result envelope. On the free Scout plan the list is capped at the top 25.

GET/v1/counties/{fips}

Current score and rank for a specific county (5-digit FIPS). Paid plans add a components breakdown.

GET/v1/counties/{fips}/historyUnderwriter plan

Historical momentum-score snapshots for a county. Returns 403 on Scout / Analyst.

GET/v1/meta

Data vintage, source attribution, and snapshot coverage.

Parameters for `/v1/counties/ranked`

Parameter	Type	Description
`limit`	integer	Rows to return (default 50; capped at 1000; `0` returns all). Scout plan is always capped at the top 25.
`offset`	integer	Pagination offset (default 0).
`state`	string	1–2 digit state FIPS prefix (e.g. `36` for New York).
`min_pop`	integer	Minimum county population (default 50000).
`blend`	string	`leading` (default) or `experimental`.
`year`	integer	Rank year (defaults to the latest available).

Try it

Your X-RapidAPI-Key comes from your RapidAPI subscription. Note state takes a FIPS prefix (36 = New York), not a 2-letter code. Pick a language:

Request

curl -X GET "https://market-momentum-screener1.p.rapidapi.com/v1/counties/ranked?state=36&limit=25" \
  -H "X-RapidAPI-Key: YOUR_KEY_HERE" \
  -H "X-RapidAPI-Host: market-momentum-screener1.p.rapidapi.com"

const url =
  "https://market-momentum-screener1.p.rapidapi.com/v1/counties/ranked?state=36&limit=25";
const res = await fetch(url, {
  headers: {
    "X-RapidAPI-Key": "YOUR_KEY_HERE",
    "X-RapidAPI-Host": "market-momentum-screener1.p.rapidapi.com"
  }
});
const data = await res.json();
console.log(data.counties);

import requests

url = "https://market-momentum-screener1.p.rapidapi.com/v1/counties/ranked"
headers = {
    "X-RapidAPI-Key": "YOUR_KEY_HERE",
    "X-RapidAPI-Host": "market-momentum-screener1.p.rapidapi.com",
}
params = {"state": "36", "limit": 25}
data = requests.get(url, headers=headers, params=params).json()
print(data["counties"])

Response

{
  "as_of": 2025,
  "blend": "leading",
  "filters": { "min_pop": 50000, "state": "36" },
  "count": 25,
  "limit": 25,
  "offset": 0,
  "attribution": "Derived analytics. Built from Realtor.com Real Estate Data Library plus U.S. Census/IRS public data; raw source values are not redistributed. Full attribution at /v1/meta.",
  "counties": [
    {
      "fips": "36037",
      "county": "Genesee County, New York",
      "rank_year": 2025,
      "canonical_rank": 1,
      "leading_score": 0.988933,
      "score": 0.988933,
      "context": { "population": 57604 }
    }
  ]
}

Response fields

Field	Notes
`as_of` / `rank_year`	The ranking vintage year.
`blend`	Which signal blend produced the ranking (`leading` / `experimental`).
`count` / `limit` / `offset`	Envelope paging. `count` may be smaller than `limit` (Scout caps at 25).
`fips` / `county`	5-digit county FIPS and "County, State" name.
`canonical_rank`	Rank within the ranking universe (1 = strongest momentum).
`leading_score` / `score`	Momentum score, 0–1 (higher = stronger momentum).
`context.population`	County population. Paid plans add `migration_rate`.
`components`	Paid plans only — signal breakdown (`cut_share_pct`, `dom_pct`, `inventory_yy_pct`, `migration_pct`).
`attribution`	Source attribution string; full detail at `/v1/meta`.

Market Momentum returns derived analytics only — scores, ranks, percentiles, and context. Raw third-party source values are not redistributed, so records carry an attribution string rather than a per-record provenance block.

Plans

Unlike our other APIs, Market Momentum plans gate features, not just call volume.

Plan	Price	What you get
Scout	Free	Top 25 ranked counties plus single-county lookup — final momentum score only. No component breakdown, no history.
Analyst	$29/mo	Full ranked universe (1,000+ counties) and single-county lookup with the signal component decomposition. No history.
Underwriter	$99/mo	Everything in Analyst, plus the full historical track record (`/history`).

Pricing as listed on RapidAPI; confirm current plan details on the RapidAPI listing.

Methodology

Listing-flow leading signal

The signal scores Realtor.com listing-flow indicators — price-cut share, days-on-market, and YoY inventory — against next-year home-value growth. It holds its sign through the 2022–2024 reversal, where trend-following migration signals invert.

Validated track record

The leading top-decile portfolio beats the county universe in every year on file (excess ~+2.2%/yr) on price appreciation alone — research evidence, not a return guarantee.

Sources

Built from Realtor.com Economic Research listing-flow indicators, U.S. Census population context, and IRS migration context. Uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.

Monthly rankings

Counties are re-ranked each month. Data vintage and snapshot coverage are reported at /v1/meta.

Errors & usage

Status	Meaning
`200`	Success.
`400`	Invalid parameter.
`403`	Request didn't arrive through the API gateway, or the endpoint isn't in your plan (e.g. `/history` without the Underwriter plan).
`404`	County not scored — unknown FIPS, below the population floor, or missing listing data.

Disclaimer

This API provides market-screening and research data. It is not financial, legal, real-estate, or investment advice. Perform your own underwriting and due diligence before making investment decisions. See Terms of Use.