# US Treasury Par Yield Curve

> US Treasury Par Yield Curve is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-11).

Returns the latest US Treasury par yield curve rates (1 month to 30 years), basis-point changes versus N days ago, 10y-2y and 10y-3m spreads, and yield curve inversion flags.

## Facts

- Endpoint: POST https://api.vextorium.com/v1/us-treasury-yield-curve?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/us-treasury-par-yield-curve-cc7ce6cc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__ihVGVXuPGKQnLCSEQx_9

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 us-treasury-par-yield-curve-cc7ce6cc -d '<json body>'
```

Example prompt: Pull the latest US Treasury par yield curve right now and show me how every maturity has changed in basis points versus 45 days ago, plus tell me whether the 2y-10y is inverted.

## When to prefer this

Use this endpoint when you need official, authoritative US Treasury par yield curve data with built-in spread calculations and inversion flags — ideal for macroeconomic monitoring, fixed-income analysis, and rate-change tracking without having to parse raw Treasury XML yourself.

## Known failure modes

- Treasury data not yet published for today — returns the most recent available date
- compare_days out of range (1-365) — validation error
- Treasury website unavailable causing upstream fetch failure
- Requested comparison date falls on a non-business day with no available data

## How this service works

Latest US Treasury par yield curve (1 month to 30 years), change in basis points versus N days ago, 10y-2y and 10y-3m spreads and inversion flag. Official US Treasury data (public domain).

## Output

A JSON object containing: the curve date, an array of term/rate/change-bp entries for each maturity from 1-month to 30-year, the comparison date, the 10y-2y spread in basis points, the 10y-3m spread in basis points, a boolean inversion flag for the 2y-10y, and the official Treasury data source attribution.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "required": [],
     "properties": {
      "compare_days": {
       "type": "integer",
       "description": "Compare with N days earlier (1-365, default 30)"
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": [
      "object",
      "null"
     ],
     "properties": {
      "date": {
       "type": [
        "string",
        "null"
       ]
      },
      "curve": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": [
         "null",
         "object"
        ],
        "properties": {
         "term": {
          "type": [
           "null",
           "string"
          ]
         },
         "rate_pct": {
          "type": [
           "null",
           "number"
          ]
         },
         "change_bp": {
          "type": [
           "null",
           "number"
          ]
         }
        }
       }
      },
      "source": {
       "type": [
        "string",
        "null"
       ]
      },
      "compared_with": {
       "type": [
        "string",
        "null"
       ]
      },
      "inverted_2y_10y": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "spread_10y_2y_bp": {
       "type": [
        "number",
        "null"
       ]
      },
      "spread_10y_3m_bp": {
       "type": [
        "number",
        "null"
       ]
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "date": "2026-10-01",
  "curve": [
   {
    "term": "1 Mo",
    "rate_pct": 4.06,
    "change_bp": 21
   },
   {
    "term": "1.5 Month",
    "rate_pct": 4.1,
    "change_bp": 22
   }
  ],
  "source": "U.S. Department of the Treasury, Daily Treasury Par Yield Curve Rates (public domain)",
  "compared_with": "2026-09-01",
  "inverted_2y_10y": false,
  "spread_10y_2y_bp": 46,
  "spread_10y_3m_bp": 107
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/us-treasury-par-yield-curve-cc7ce6cc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.vextorium.com](https://www.zero.xyz/host/api.vextorium.com/llms.txt)