# x402 AI Gateway – Currency Amount Conversion

> x402 AI Gateway – Currency Amount Conversion is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0002/call, status unknown (last checked 2026-10-12).

Converts a specified amount of a source currency, returning the converted value, gated behind an x402 USDC micropayment.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/gnf?utm_source=zero.xyz
- Price: $0.0002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ai-gateway-currency-amount-conversion-374ae8eb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_91WyqnSUoAaagxqFS7IH2

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 x402-ai-gateway-currency-amount-conversion-374ae8eb -d '<json body>'
```

Example prompt: Convert 250 units of the source currency for me — I'm okay with the $0.0002 USDC micropayment on Base to run the call.

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call currency amount conversion that requires no subscription or API key — only a small USDC micropayment on Base via the x402 protocol. It is best suited for agent workflows that need sporadic, low-cost currency conversions without committing to a monthly plan.

## Known failure modes

- Payment not provided or insufficient USDC balance — 402 Payment Required returned before execution
- Invalid or missing 'amount' field — 422 Unprocessable Entity or validation error
- Gateway unreachable or self-hosted service down — 502/503 error
- Amount is zero or negative — may return error or undefined result
- Unsupported currency pair — empty or error response from underlying logic

## How this service works

Self-hosted AI API gateway. Expensive endpoints require an x402 micropayment (USDC on Base) before executing.

## Output

A JSON object containing the conversion result for the specified amount; the exact fields depend on the gateway's underlying currency conversion logic, but typically includes the converted value or equivalent amount.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "amount": {
   "type": "number",
   "description": "Amount of the source currency to convert (default 1)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-ai-gateway-currency-amount-conversion-374ae8eb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.fastapi.online](https://www.zero.xyz/host/api.fastapi.online/llms.txt)