# ECB FX Rate Historical Series

> ECB FX Rate Historical Series is a paid API for AI agents from x402.professorsausages.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Returns a per-pair historical fixing series over a date range (daily, weekly, or monthly) with min, max, avg, and percent-change stats, covering ECB reference rates back to 1999.

## Facts

- Endpoint: POST https://x402.professorsausages.com/fx-rates/history
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ecb-fx-rate-historical-series-e98e173b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nB1Koub5XT1F00QMdKU4I

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability ecb-fx-rate-historical-series-e98e173b -d '<json body>'
```

Example prompt: Can you pull the monthly EUR/USD ECB fixing series from January 2020 to December 2023, including the min, max, average, and percent change over that period?

## When to prefer this

Choose this endpoint when you need a time-series of ECB official reference rates for a specific currency pair over a date range, with aggregated statistics. Prefer it over single-rate lookups when you need trend analysis, volatility stats, or charting data. It complements the single-date cross-rate endpoint when historical depth or interval aggregation is required.

## Known failure modes

- Unsupported currency pair (not covered by ECB fixings) returns an error or empty points array
- Invalid date range (e.g. before 1999 or future dates) may return empty or partial results
- Malformed interval value (not daily/weekly/monthly) causes a validation error
- Network or payment authorization failure returns a 402 or 5xx error

## Output

Returns an array of [fixingDate, rate] data points for the specified currency pair and interval, plus aggregate stats (min, max, avg, first, last, changePct) over the requested date range, and metadata about the rate type (ecb-daily-reference) and data source.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ecb-fx-rate-historical-series-e98e173b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.professorsausages.com](https://www.zero.xyz/host/x402.professorsausages.com/llms.txt)