Reverse geocode

Resolve a lat/lon to a structured postal address: road, house number, city, state, postcode, country (with ISO code). OpenStreetMap/Nominatim, no key. ?lat=38.8977&lon=-77.0365.

Input

Field	Type	Description
lat *	number	Latitude, -90 to 90
lon *	number	Longitude, -180 to 180
zoom	number	Detail level, 3 (country) to 18 (building). Default 18.

Example output

{
  "lat": 38.8977,
  "lon": -77.0365,
  "displayName": "White House, 1600, Pennsylvania Avenue Northwest, Washington, District of Columbia, 20500, United States",
  "address": {
    "houseNumber": "1600",
    "road": "Pennsylvania Avenue Northwest",
    "city": "Washington",
    "state": "District of Columbia",
    "postcode": "20500",
    "country": "United States",
    "countryCode": "us"
  },
  "type": "attraction",
  "class": "tourism",
  "osm": "way/238241022",
  "source": "nominatim.openstreetmap.org (ODbL)"
}

Try it — see the 402 challenge (free)

curl -i "https://agent402.tools/api/reverse-geocode?lat=38.8977&lon=-77.0365"

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/reverse-geocode?lat=38.8977&lon=-77.0365");

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits — a fraction of a second of CPU, no money, no AI tokens), and resend with the X-Pow-Solution header.

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=reverse-geocode")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/reverse-geocode", { method: "GET", headers: { "X-Pow-Solution": c.token + ":" + n } });

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