# US Treasury Par Yield Curve Rates

> US Treasury Par Yield Curve Rates is a paid API for AI agents from x402helper.xyz, paid per call via x402, $0.0195/call, status unknown (last checked 2026-10-31).

Returns US Treasury par yield curve rates for a specified calendar year, accessible via x402 USDC micropayment.

## Facts

- Endpoint: GET https://x402helper.xyz/89e509/treasury/rates?utm_source=zero.xyz
- Price: $0.0195/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/us-treasury-par-yield-curve-rates-60e8e0c5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wE2x_vHwYgi-knVoJR2Dw

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-rates-60e8e0c5
```

Example prompt: Can you pull the US Treasury par yield curve rates for 2022? I need the benchmark yield data for that calendar year.

## When to prefer this

Choose this endpoint when you need US Treasury par yield curve data and are operating in an x402-capable agent environment that can handle USDC micropayments. Suitable for financial modeling, fixed income benchmarking, or macro research workflows where programmatic access to government yield data is needed without a traditional API key subscription.

## Known failure modes

- Year out of supported range (1990–2100) returns validation error
- Treasury data unavailable for requested year returns empty or error result
- Payment failure via x402 protocol blocks access to the endpoint
- Invalid query parameter type (non-integer year) causes request rejection
- Network timeout if Treasury data source is temporarily unavailable

## How this service works

X402 micropayments server — AI agents pay USDC for OFAC screening, rates, and billing verification.

## Output

Returns a JSON object containing US Treasury par yield curve rates for the requested year (or current year by default), including yield values across various maturities. Response includes a success flag and a result object with the rate data.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "year": {
       "type": "integer",
       "default": null,
       "maximum": 2100,
       "minimum": 1990,
       "description": "Calendar year of the par yield curve (default current)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {},
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/us-treasury-par-yield-curve-rates-60e8e0c5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402helper.xyz](https://www.zero.xyz/host/x402helper.xyz/llms.txt)