Reverse geocode

Resolve a lat/lon to a structured postal address: road, house number, city, state, postcode, country (with ISO code). Send GET /api/reverse-geocode with the required fields lat and lon and pay $0.001 per call over x402 or MPP (there is no free tier). It returns a JSON object with lat, lon, displayName, address, type and 3 more.

OpenStreetMap/Nominatim, no key. ?lat=38.8977&lon=-77.0365.

Category: Live public data · Tags: reverse-geocoding address lat-lon openstreetmap nominatim maps

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Parameters

Example request

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

Without payment this returns HTTP 402 Payment Required with the exact price for reverse-geocode; any x402 v2 or MPP client pays it and retries.

Example response

{
  "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)"
}

From an MCP client

catalog.call {
  "slug": "reverse-geocode",
  "params": {
    "lat": 38.8977,
    "lon": -77.0365
  }
}

The hosted connector at https://agent402.tools/mcp needs a payment for reverse-geocode; the stdio package pays it from a wallet or from AGENT402_CREDITS_KEY. Local install: npx -y agent402-mcp.

Errors and behavior

• lat and lon are required. An input the tool rejects returns an HTTP 4xx whose body carries error, tool, expected, required and example, so the caller can correct it.
• A paid call that ends in any status of 400 or above is not charged over x402, MPP or a prepaid credits key: settlement is cancelled when the tool fails. The exception is a Tempo push credential, a transfer the buyer sent before the call: it settles before the tool runs, so if the tool then fails the payment is recorded as a refund owed to the paying wallet.
• Wallet-only: this tool reaches the network or stored state, so it has no proof-of-work tier. A prepaid card-credits key issued earlier (Authorization: Bearer a402_...) also pays it.
• Cached: an identical request within 1d is answered from cache with X-Cache: hit.
• A POST with a JSON body to /api/reverse-geocode is served as this GET, with the body as the input.
• An Idempotency-Key header makes a retried paid call replay the first 200 instead of charging again (an answer larger than 1 MB is not replayed).

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();
client.setSpendControls?.(false); // keep your own spending ceiling in code
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");

Part of these workflows

Reverse geocode is one step in this skill pack, each sold as a single call:

• Location intel - Point at an address (or even a rough place name) and assemble the situational brief: precise coordinates, the canonical postal address, what's within walking distance, the live weather forecast, active NWS hazard alerts, and recent seismic activity. The deterministic 'what should I know about this place right now?' workup.

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