# US Treasury Average Interest Rates

> US Treasury Average Interest Rates is a paid API for AI agents from data.greeneris.io, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Returns monthly average interest rates the US Treasury pays on outstanding securities, sourced from the official FiscalData API, filterable by security type and date range.

## Facts

- Endpoint: GET https://data.greeneris.io/v1/us/treasury-rates
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/us-treasury-average-interest-rates-730c23a5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CG5x4ji0yirHu3UEm9X0Z

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-average-interest-rates-730c23a5
```

Example prompt: Can you pull the monthly average interest rates the US Treasury has been paying on Treasury Bills since January 2024, up to the last 12 records?

## When to prefer this

Use this endpoint when you need official US Treasury average interest rate data by security type (Bills, Notes, Bonds, etc.) on a monthly basis, sourced directly from the FiscalData API. Prefer it over scraping Treasury websites or using third-party rate aggregators when you need clean, normalized, cached JSON with filtering by security type and date.

## Known failure modes

- Invalid security_desc value returns empty results (no matching records found)
- since date in wrong format returns a 400 error
- limit outside 1-100 range returns a 400 validation error
- FiscalData upstream outage may cause 502/503 error
- Payment of 0.005 USDC not completed returns 402 Payment Required

## How this service works

Monthly average interest rates the US Treasury pays on its outstanding securities, from the official FiscalData API (Average Interest Rates dataset, updated monthly). Query: ?security=Treasury Bills (exact security_desc, optional; e.g. Treasury Notes, Treasury Bonds) &since=2026-01-01 (optional record_date floor) &limit=12 (1-100, newest first). Returns record_date, security type/name and avg rate in percent. Cached 24h.

## Output

A JSON array of records each containing record_date (ISO date), security type/name, and average interest rate in percent, sorted newest first, cached up to 24 hours.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "limit": {
       "type": "integer",
       "default": 12,
       "description": "Max records, newest first (1-100)"
      },
      "since": {
       "type": "string",
       "description": "Only records with record_date >= this ISO date"
      },
      "security": {
       "type": "string",
       "description": "Exact security_desc filter, e.g. Treasury Bills"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 2,
  "rates": [
   {
    "security": "Treasury Bills",
    "record_date": "2026-06-30",
    "security_type": "Marketable",
    "avg_interest_rate_pct": 3.706
   },
   {
    "security": "Treasury Bills",
    "record_date": "2026-05-31",
    "security_type": "Marketable",
    "avg_interest_rate_pct": 3.741
   }
  ],
  "source": "US Treasury FiscalData API, Average Interest Rates on Treasury Securities (monthly, public domain)"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/us-treasury-average-interest-rates-730c23a5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from data.greeneris.io](https://www.zero.xyz/host/data.greeneris.io/llms.txt)