# Ambolt US Treasury Rates

> Ambolt US Treasury Rates is a paid API for AI agents from api.ambolt.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-11).

Returns month-end average interest rates for US Treasury Bills, Notes, and Bonds for up to 24 recent months.

## Facts

- Endpoint: GET https://api.ambolt.dev/v1/us-treasury-rates?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ambolt-us-treasury-rates-2132aa31
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gp-LujP7NSCxjpSOMLI78

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 ambolt-us-treasury-rates-2132aa31
```

Example prompt: What are the US Treasury Bill, Note, and Bond average interest rates for the last 6 months?

## When to prefer this

Use this endpoint when you need official, sourced US Treasury average interest rates (Bills, Notes, Bonds) for up to 24 recent months, especially in financial modeling, macro analysis, or dashboards requiring government-backed rate data. Prefer it over scraping Treasury websites or using third-party financial data providers when you want a pay-per-call model without a subscription and need data attributed directly to the US Treasury Fiscal Data source.

## Known failure modes

- months parameter out of range (must be 1–24): likely returns a 400 or validation error
- Payment not included or insufficient USDC: returns HTTP 402 Payment Required
- Upstream Treasury Fiscal Data unavailable: may return 503 or stale data
- Invalid query parameter types: schema validation failure

## How this service works

Pay-per-call data tools for developers and AI agents: company registers, documents, tenders, rates and on-chain facts as MCP tools, x402 endpoints and Apify Actors.

## Output

A JSON object containing an array of monthly records, each with a record date and a list of securities (Treasury Bills, Treasury Notes, Treasury Bonds) with their average interest rates as percentages. Also includes a source attribution string from the US Treasury Fiscal Data and a fetchedAt timestamp.

## 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": {
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "POST"
     ]
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "months": {
       "type": "integer",
       "default": 3,
       "maximum": 24,
       "minimum": 1,
       "description": "Number of most recent months."
      }
     },
     "additionalProperties": false
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "months": [
   {
    "rates": [
     {
      "ratePct": 3.788,
      "security": "Treasury Bills"
     },
     {
      "ratePct": 3.345,
      "security": "Treasury Notes"
     },
     {
      "ratePct": 3.453,
      "security": "Treasury Bonds"
     }
    ],
    "recordDate": "2026-08-31"
   },
   {
    "rates": [
     {
      "ratePct": 3.758,
      "security": "Treasury Bills"
     },
     {
      "ratePct": 3.309,
      "security": "Treasury Notes"
     },
     {
      "ratePct": 3.442,
      "security": "Treasury Bonds"
     }
    ],
    "recordDate": "2026-07-31"
   }
  ],
  "source": "Source: U.S. Department of the Treasury, Fiscal Data (public domain). Average interest rates are month-end averages on outstanding securities, not market yields.",
  "fetchedAt": "2026-10-02T21:36:03.043Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ambolt-us-treasury-rates-2132aa31/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.ambolt.dev](https://www.zero.xyz/host/api.ambolt.dev/llms.txt)