# Treasury Yield Curve History (x402 Supply)

> Treasury Yield Curve History (x402 Supply) is a paid API for AI agents from treasury-yield-curve.x402supply.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-18).

Returns US Treasury par yield curve data (1mo to 30yr maturities, in percent) for a range of business days between a start and end date.

## Facts

- Endpoint: POST https://treasury-yield-curve.x402supply.com/tools/yield_curve_history?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/treasury-yield-curve-history-x402-supply-5dffd4cf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qldiGr-bPvV43QU8ikEXp

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 treasury-yield-curve-history-x402-supply-5dffd4cf -d '<json body>'
```

Example prompt: Can you pull the US Treasury par yield curve for every business day from March 1 to March 31, 2024 — I want to see all the maturities from 1-month out to 30 years?

## When to prefer this

Choose this endpoint when you need historical US Treasury par yield curve data across a range of business days (up to 31 days per call). It is ideal for multi-day trend analysis, spread calculations, or building time-series of risk-free rates across the full maturity spectrum. Prefer the sibling single-date endpoint for one-off point-in-time lookups. Use this over general financial data APIs when you specifically need official US Treasury par yield data sourced directly from treasury.gov.

## Known failure modes

- Date out of range — startDate before 1990-01-02 returns an error
- Date range exceeds 31 days between startDate and endDate
- Invalid date format (non-YYYY-MM-DD) returns a validation error
- Weekend or holiday startDate/endDate is shifted to nearest prior business day automatically
- Future dates beyond today return no data or a capped response
- Treasury source data temporarily unavailable may cause fetch failure

## How this service works

US Treasury par yield curve (1mo to 30yr, percent) for one date, or the latest if omitted. Weekend or holiday dates return the nearest prior business day with a note. Data from U.S. Treasury; not financial advice.; US Treasury par yield curves for every business day between startDate and endDate (ma

## Output

A JSON object containing an array of yield curves, one per business day in the requested range. Each curve entry includes the date and a yields map keyed by maturity label (1mo, 2mo, 1.5mo, 3mo, 4mo, 6mo, 1yr, 2yr, 3yr, 5yr, 7yr, 10yr, 20yr, 30yr) with percent values. Also includes metadata: count of curves returned, unit (percent), asOf timestamp, source URL(s), and the resolved startDate/endDate used.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "endDate": {
   "type": "string",
   "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
   "description": "YYYY-MM-DD, at most 31 days after startDate. Defaults to startDate plus 30 days, capped at today"
  },
  "startDate": {
   "type": "string",
   "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
   "description": "YYYY-MM-DD, 1990-01-02 or later"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "asOf": "2026-10-09T17:48:01.949Z",
  "unit": "percent",
  "count": 2,
  "curves": [
   {
    "date": "2026-10-01",
    "yields": {
     "1mo": 4.06,
     "1yr": 4.44,
     "2mo": 4.13,
     "2yr": 4.78,
     "3mo": 4.17,
     "3yr": 4.91,
     "4mo": 4.26,
     "5yr": 5.01,
     "6mo": 4.27,
     "7yr": 5.12,
     "10yr": 5.24,
     "20yr": 5.64,
     "30yr": 5.61,
     "1.5mo": 4.1
    }
   },
   {
    "date": "2026-10-02",
    "yields": {
     "1mo": 4.04,
     "1yr": 4.46,
     "2mo": 4.11,
     "2yr": 4.83,
     "3mo": 4.19,
     "3yr": 4.96,
     "4mo": 4.26,
     "5yr": 5.06,
     "6mo": 4.27,
     "7yr": 5.17,
     "10yr": 5.28,
     "20yr": 5.67,
     "30yr": 5.63,
     "1.5mo": 4.09
    }
   }
  ],
  "source": [
   "https://home.treasury.gov/resource-center/data-chart-center/interest-rates/pages/xml?data=daily_treasury_yield_curve&field_tdr_date_value_month=202610"
  ],
  "endDate": "2026-10-02",
  "startDate": "2026-10-01"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/treasury-yield-curve-history-x402-supply-5dffd4cf/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from treasury-yield-curve.x402supply.com](https://www.zero.xyz/host/treasury-yield-curve.x402supply.com/llms.txt)