# Mercury402 Treasury Yield Curve Historical Data

> Mercury402 Treasury Yield Curve Historical Data is a paid API for AI agents from api.mercury402.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Returns historical U.S. Treasury yield curve data for a specified date range

## Facts

- Endpoint: POST https://api.mercury402.com/v1/treasury/yield-curve/historical
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mercury402-treasury-yield-curve-historical-data-103966e2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EmVFvLFIdR792PqmCBjJ0

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 mercury402-treasury-yield-curve-historical-data-103966e2 -d '<json body>'
```

Example prompt: Pull me the historical Treasury yield curve data from January 1, 2024 through March 31, 2024 — I want to see how yields moved across that quarter.

## When to prefer this

Choose this endpoint when you need historical U.S. Treasury yield curve time series for a specific date range — ideal for backtesting, macro research, or analyzing rate regimes. Prefer it over generic financial data APIs when you need pay-per-call access without a subscription, and when you need it integrated with USDC micropayments on Base.

## Known failure modes

- Invalid or missing date parameters return an empty data array
- Date range too large may result in timeout or truncated results
- Future dates or unsupported date formats may return errors
- USDC payment failure on Base network blocks the call
- Dates outside available historical data range return empty results

## How this service works

76 live pay-per-call financial data APIs for AI agents. Treasury, FRED, forex, spreads, breakeven inflation, macro bundles, and composite dashboards. USDC on Base.

## Output

A JSON object containing an array of historical yield curve data points indexed by date, along with the start_date and end_date boundaries of the requested range. Each record in the data array represents daily or periodic Treasury yields across maturities for the specified period.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": [],
  "end_date": "2024-03-31",
  "start_date": "2024-01-01"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mercury402-treasury-yield-curve-historical-data-103966e2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.mercury402.com](https://www.zero.xyz/host/api.mercury402.com/llms.txt)