# StationFX 30-Year U.S. Treasury Constant Maturity Yield

> StationFX 30-Year U.S. Treasury Constant Maturity Yield is a paid API for AI agents from stationfx.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).

Returns daily U.S. 30-year Treasury bond yield data with rich statistical enrichments including z-scores, percentile ranks, trend indicators, and rolling averages.

## Facts

- Endpoint: GET https://stationfx.com/economic-data/interest-rates/market-yield-on-u-s-treasury-securities-at-30-year-constant-maturity-quoted-on-an-investment-basis?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stationfx-30-year-u-s-treasury-constant-maturity-yield-92512bf5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qfEI9tgcxK2YszyMVD6oI

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 stationfx-30-year-u-s-treasury-constant-maturity-yield-92512bf5
```

Example prompt: What's the current 30-year U.S. Treasury yield, and how does it compare to its 5-year historical range? Pull the latest data from StationFX in JSON format.

## When to prefer this

Choose this endpoint when you need the U.S. 30-year Treasury yield specifically — the ultra-long end of the curve most sensitive to long-run inflation expectations and fiscal risk. Prefer it over the 10-year endpoint for pension/insurance liability matching, ultra-long duration analysis, or when studying fiscal sustainability concerns. It includes pre-computed statistical enrichments (z-scores, percentile ranks, trend flags) that save downstream computation versus raw FRED data.

## Known failure modes

- Missing or invalid date_from/date_to format returns an error or empty dataset
- Requesting future dates returns no data (daily frequency, not forward-looking)
- Weekend or holiday dates may return no observation for that specific day
- Invalid fmt enum value may cause a format error
- Network or payment (x402) failure returns HTTP 402 or connection error

## How this service works

Ultra-long U.S. government bond yield representing 30-year borrowing costs. Most sensitive to long-run inflation expectations and fiscal concerns. Used for duration analysis and pension/insurance liability matching. Daily frequency.

## Output

Returns a JSON array of daily observations, each containing the date, raw 30-year yield value (in percent), month-over-month and year-over-year absolute and percentage changes, 12-month and 5-year z-scores, 5-year percentile rank, 3-month and 12-month rolling averages, and a binary above-trend indicator. Supports compact 'toon' format for agent-friendly consumption.

## 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",
     "description": "Always \"http\" for HTTP endpoints"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string",
     "description": "HTTP method. Always GET for StationFX query endpoints"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "fmt": {
       "enum": [
        "json",
        "toon"
       ],
       "type": "string",
       "description": "Response format. Use toon for compact agent-friendly output."
      },
      "fields": {
       "type": "string",
       "description": "Comma-separated metric names"
      },
      "date_to": {
       "type": "string",
       "description": "End date YYYY-MM-DD"
      },
      "date_from": {
       "type": "string",
       "description": "Start date YYYY-MM-DD"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "description": "Response format. Always \"json\" (or \"toon\" if fmt=toon was requested)"
    },
    "example": {
     "type": "object",
     "properties": {
      "data": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "date": {
          "type": "string",
          "description": "Observation date YYYY-MM-DD"
         },
         "value": {
          "type": "number",
          "description": "Raw observed value in series units"
         },
         "mom_pct": {
          "type": "number",
          "description": "Month-over-month % change"
         },
         "yoy_pct": {
          "type": "number",
          "description": "Year-over-year % change"
         },
         "zscore_5y": {
          "type": "number",
          "description": "Z-score relative to trailing 5 years"
         },
         "mom_change": {
          "type": "number",
          "description": "Month-over-month absolute change"
         },
         "yoy_change": {
          "type": "number",
          "description": "Year-over-year absolute change"
         },
         "zscore_12m": {
          "type": "number",
          "description": "Z-score relative to trailing 12
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "schema": {
  "type": "object",
  "properties": {
   "data": {
    "type": "array",
    "items": {
     "type": "object",
     "properties": {
      "date": {
       "type": "string",
       "description": "Observation date YYYY-MM-DD"
      },
      "value": {
       "type": "number",
       "description": "Raw observed value in series units"
      },
      "mom_pct": {
       "type": "number",
       "description": "Month-over-month % change"
      },
      "yoy_pct": {
       "type": "number",
       "description": "Year-over-year % change"
      },
      "zscore_5y": {
       "type": "number",
       "description": "Z-score relative to trailing 5 years"
      },
      "mom_change": {
       "type": "number",
       "description": "Month-over-month absolute change"
      },
      "yoy_change": {
       "type": "number",
       "description": "Year-over-year absolute change"
      },
      "zscore_12m": {
       "type": "number",
       "description": "Z-score relative to trailing 12 months"
      },
      "above_trend": {
       "type": "integer",
       "description": "1 if value is above long-run trend, else 0"
      },
      "pct_rank_5y": {
       "type": "number",
       "description": "Percentile rank over trailing 5 years (0-100)"
      },
      "rolling_3m_avg": {
       "type": "number",
       "description": "3-month rolling average"
      },
      "rolling_12m_avg": {
       "type": "number",
       "description": "12-month rolling average"
      },
      "trend_direction": {
       "type": "integer",
       "description": "Trend: 1 rising, -1 falling, 0 flat"
      }
     }
    },
    "description": "Observations ordered by date ascending"
   },
   "meta": {
    "type": "object",
    "description": "Series metadata: source_key (FRED series ID), units, frequency (D/W/M/Q/A), date_from, date_to, fields"
   }
  },
  "description": "Station f(x) response with metadata and pre-computed derived metrics"
 },
 "example": {
  "data": [
   {
    "date": "2024-01-01",
    "value": 5.33,
    "mom_pct": 0,
    "yoy_change": 0.5,
    "zscore_12m": 1.2,
    "trend_direction": 1
   }
  ],
  "meta": {
   "frequency": "D",
   "source_key": "DGS30"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/stationfx-30-year-u-s-treasury-constant-maturity-yield-92512bf5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from stationfx.com](https://www.zero.xyz/host/stationfx.com/llms.txt)