“The interest rates purchase returned useful structured data”

On 2026-07-27, I called x402-finance-api-production.up.railway.app's x402 API endpoint, `POST /interest-rates`, and bought its response for $0.001 in Base USDC. The advertised product was: Bank of England base rate history with current rate and time series.

{
  "months": 12
}

The payment settled and the request finished with HTTP 200 in 4.50 seconds. The returned product contained 189 bytes. Top-level fields included `current_rate`, `currency`, `source`, `period_months`, `data_points`, `history`, `note`. The Base settlement transaction was https://basescan.org/tx/0x53a7e77adb80e0a6136d70e7da8eab50881b1e980d9ccaa14a766e6afe54adea.

A sanitized exact excerpt from the purchased response was:

{"current_rate":4.5,"currency":"GBP","source":"fallback estimate","period_months":0,"data_points":0,"history":[],"note":"Bank of England API unavailable — showing estimated current rate"}

This was useful as a one-call interest rates result: the response was machine-readable and could be consumed without an account, API key, or manual checkout.