# usaref Certified Country/Series Lookup

> usaref Certified Country/Series Lookup is a paid API for AI agents from usaref.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-10-30).

Returns a single certified, source-cited government reference value (e.g. policy rate, VAT rate, CPI, minimum wage) for a specified North American country and data series

## Facts

- Endpoint: GET https://usaref.dev/v1/certified/%7Bcountry%7D/%7Bseries%7D?utm_source=zero.xyz
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/usaref-certified-country-series-lookup-8f7abb42
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_z8SmsTp12ySFMTkiI8VY-

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-certified-country-series-lookup-8f7abb42
```

Example prompt: What is the current VAT rate for Mexico — I need the official government-cited figure with its source URL and the date it was last confirmed?

## When to prefer this

Choose this endpoint when you need a single, officially cited government reference value for one specific country and one specific data series (e.g. VAT rate for Mexico, policy rate for Canada). It is the right choice when auditability and provenance matter — every value includes its official source URL and last-confirmed date. Prefer it over general web search or LLM recall when you need machine-readable, structured, and citable compliance-grade data for North American jurisdictions.

## Known failure modes

- Country not covered by the service — returns an error or refusal indicating unsupported country
- Series not available for the requested country — endpoint refuses with an explanation of coverage limits
- Invalid country or series path parameter — returns a 400 or 404 error
- Payment not completed or insufficient credit — returns a 402 Payment Required response
- Stale data flag present — value returned but marked as potentially outdated via a 'stale' field

## How this service works

North American government reference data for 10 countries as cited JSON: central-bank policy rates, VAT/GST and VAT registration thresholds, CPI, corporate, personal and withholding tax, social contributions, minimum wages, statutory interest, official FX rates, filing deadlines and public holidays (coverage varies by country). Every value carries its official source URL and last-confirmed date. Single facts $0.003; country brief (every series for one country) $0.01; cross-country compare (one series, up to 10 countries) $0.02; tax-ID and VAT-number checks $0.003; computed answers (VAT, income tax, working days, minimum-wage check) $0.01-$0.02. Pay per call in USDC on Base via x402 or MPP, no signup, or by card with credit packs or monthly plans on one key valid across all 7 regional services. Free tier: GET /catalog, plus a free email key with 50 answer calls a day, commercial use allowed. Finished answers, one cited dossier per call (supported countries vary per job; others are refused free): cost this hire (wage-floor verdict, contributions, employer cost) $0.50; charge this sale (which VAT applies, net/VAT/gross) $0.50; charge this sale certified (plus a signed VAT-rate extract) $0.75; invoice due date and statutory late interest $0.40; country evidence pack (brief plus signed extracts) $0.25; hire compare $0.75 for 2 countries, $1.00 for 3-5; next filings (VAT, PAYE, corporate-tax due dates rolled for holidays) $0.35.

Free trial: 3 computed-answer calls per day per IP on POST /v1/answers/* with header X-Free-Trial: 1 (without it, the normal x402 402; once used up, the 402 carries free_trial_resets_at). MCP answer tools use the trial automatically when no api_key is passed. Every series of the evaluation country is free. Card credit (same per-call price as x402): /pricing.

## Output

A JSON object containing the official government reference value for the requested country and data series, including the numeric value with units, the official source URL from which it was drawn, and the last-confirmed date. The response is structured as a single cited dossier for the specified series/country pair.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/usaref-certified-country-series-lookup-8f7abb42/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)