A useful response in one request.

Read rates and freshness together.

OpenAPI with response schemas
Agent context

const response = await fetch(
  "https://bitcoinsapi.com/api/v1/fees/preview",
  { signal: AbortSignal.timeout(5000) }
);
if (!response.ok) throw new Error(`Fee API: ${response.status}`);
const { data, meta } = await response.json();
const age = (Date.now() - Date.parse(meta.fetched_at)) / 1000;
// Allow up to 30 seconds of clock skew between the client and server.
if (meta.stale || !Number.isFinite(age) || age < -30 || age > 60) {
  throw new Error("Request a fresher snapshot before using these fees");
}
const vbytes = 140; // Replace with your wallet's estimate.
const feeSats = Math.ceil(data.fee_rates_sat_vb.hour * vbytes);
console.log({ feeSats, source: meta.source });

The example applies a 60-second freshness policy and allows 30 seconds of clock skew. The API may serve a fallback up to 120 seconds old at the origin, plus HTTP cache time. A rate target is not a confirmation guarantee.

Add a paid decision only when you need it.

PausedPayments are paused. No payment proof is processed. The free fee preview is available without a wallet.

The optional GET /api/v1/fees/now route costs 0.001 USDC on Base mainnet when enabled. It adds a deterministic send-or-wait result, reason codes, and a confirmed settlement receipt. It uses the same public source data; it is not a proprietary forecast.

curl --fail-with-body https://bitcoinsapi.com/status.json
curl -i https://bitcoinsapi.com/api/v1/fees/now

These ordinary HTTP requests do not sign or pay. While paused, the second returns 503 payments_disabled without a challenge. When enabled, inspect PAYMENT-REQUIRED and use an official x402 v2 client with your own explicit spending policy. The v1 X-PAYMENT header is not supported.

Use the exact HTTPS URL with no query parameters. Check the payment contract and decision method before signing. The project discovery document is not a Bazaar registration or a hosted MCP server.