# usaref Changes Feed – North American Government Reference Data

> usaref Changes Feed – North American Government Reference Data is a paid API for AI agents from usaref.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Returns a list of government reference data series (policy rates, VAT, minimum wages, public holidays) that have changed since a given date for Canada and/or the US.

## Facts

- Endpoint: GET https://usaref.dev/v1/changes
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/usaref-changes-feed-north-american-government-reference-data-b844e70d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1scgaUyrWr5tQq7XkWy54

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 usaref-changes-feed-north-american-government-reference-data-b844e70d
```

Example prompt: What North American government reference data series have changed since July 1, 2026? I care about Canada and the US — things like minimum wages, central bank rates, VAT, and public holidays.

## When to prefer this

Choose this endpoint when you need to detect which government reference data series have been updated since a specific date, rather than fetching current values directly. It is ideal for change-detection workflows, compliance monitoring, and cache invalidation — use it to poll for updates and then fetch only the changed series in detail. Prefer it over querying individual series endpoints when you don't know which data has changed.

## Known failure modes

- Invalid or missing 'since' date parameter returns an error
- Unsupported country code returns an error or empty result
- No changes since the specified date returns an empty changes array
- Stale data if the source has not been re-confirmed recently (flagged via staleness field)
- Payment failure (x402 protocol) if USDC is not provided or insufficient

## How this service works

Authoritative North American government reference values as clean JSON: central-bank policy rates, VAT rates, national minimum wages and public holidays for Canada (ca), United States (us). Every value carries a citation to its official primary source (government gazette or central-bank statement), an effective date, a last-confirmed date and a staleness flag.

## Output

A JSON object with a 'since' date and a 'changes' array. Each change entry includes the series name (e.g. 'minimum-wage'), the country code (e.g. 'us' or 'ca'), and the effective date of the change. Each value in the broader API carries a citation to its official primary source, an effective date, a last-confirmed date, and a staleness flag.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "since": "2026-07-01",
  "changes": [
   {
    "series": "minimum-wage",
    "country": "AR",
    "effective_from": "2026-07-01"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/usaref-changes-feed-north-american-government-reference-data-b844e70d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from usaref.dev](https://www.zero.xyz/host/usaref.dev/llms.txt)