Every US address, instantly resolved.

// npm install node-fetch (or use built-in fetch)
const GC_KEY = process.env.GC_API_KEY;

async function verifyAddress(street, city, state) {
  const url = `https://geoclear.io/api/address
    ?street=${encodeURIComponent(street)}
    &city=${encodeURIComponent(city)}
    &state=${state}`;

  const res = await fetch(url, {
    headers: { 'X-Api-Key': GC_KEY }
  });
  return res.json();
}

const result = await verifyAddress(
  '350 Fifth Ave', 'New York', 'NY'
);
console.log(result.county_fips); // "36061"

import requests, os

GC_KEY = os.environ["GC_API_KEY"]

def verify_address(street, city, state):
    resp = requests.get(
        "https://geoclear.io/api/address",
        params={
            "street": street,
            "city": city,
            "state": state
        },
        headers={"X-Api-Key": GC_KEY}
    )
    resp.raise_for_status()
    return resp.json()

data = verify_address("350 Fifth Ave", "New York", "NY")
print(data["census_tract"])  # "010700"

{
  "ok":           true,
  "address":       "350 5th Ave",
  "city":          "New York",
  "state":         "NY",
  "zip":           "10118",
  "county":        "New York",
  "county_fips":   "36061",
  "census_tract":  "010700",
  "lat":           40.7484,
  "lon":           -73.9967,
  "timezone":      "America/New_York",
  "fema_zone":     "X",
  "plus4":         "1901",
  "rdi":           "Commercial",
  "status":        "verified"
}