Monitoring · x402 · early usage

Returns hourly surface concentrations from the CAMS European air-quality ensemble for a…

by karte.halowerk.com · discovered, not yet claimed by its owner · updated 2026-10-08

30d calls2

30d payers2

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Returns hourly surface concentrations from the CAMS European air-quality ensemble for a point in the cached DACH and Central Europe area. Available pollutants are CO, NO2, NO, O3, PM2.5, PM10 and SO2. Values come from the nearest 0.1 degree model cell and are labelled as a regional forecast rather than a street-level sensor reading. The local cutout is refreshed independently of paid calls, so Copernicus processing latency is not passed to the caller.

Tags: bazaar

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-08

Input example from Bazaar metadata

{
  "latitude": 45,
  "longitude": 5
}

No output exampleProvider did not publish one in Bazaar metadata.

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/55473.json for the price and payment options.
Pay. Call GET https://karte.halowerk.com/v1/air-quality. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.005 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 2 calls · 2 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.005	0x2880EdfFF13100677Bf97A3CBdF3Bc34771C4E5E	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x2880EdfFF13100677Bf97A3CBdF3Bc34771C4E5E",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "5000",
    "amountUsd": 0.005,
    "maxTimeoutSeconds": 300
  }
]

Examples

curl

curl -X POST 'https://karte.halowerk.com/v1/air-quality' -H 'Content-Type: application/json' --data '{"latitude":45,"longitude":5}'
# -> 402 Payment Required; read PAYMENT-REQUIRED
# retry the identical request with PAYMENT-SIGNATURE

JavaScript

const res = await fetch("https://karte.halowerk.com/v1/air-quality", {
  "method": "POST",
  "headers": {
    "content-type": "application/json"
  },
  "body": "{\"latitude\":45,\"longitude\":5}"
});
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
import json
res = httpx.request("POST", "https://karte.halowerk.com/v1/air-quality", json=json.loads("{\"latitude\":45,\"longitude\":5}"))
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: karte.halowerk.com
Endpoint: https://karte.halowerk.com/v1/air-quality
Machine-readable: /resources/55473.json