# x402 AI Gateway – Currency Amount Converter

> x402 AI Gateway – Currency Amount Converter 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, gated behind an x402 micropayment in USDC on Base before execution.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/aoa/xcg?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-converter-fff04ac0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_86yqwoCJE7qCnVOcvT5z1

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-converter-fff04ac0 -d '<json body>'
```

Example prompt: Convert 50 units of currency using the x402-gated API on fastapi.online — the micropayment of $0.0002 USDC on Base will be handled automatically.

## When to prefer this

Choose this endpoint when you need a pay-per-call currency conversion gated by x402 micropayments in USDC on Base, particularly in agentic workflows where autonomous micropayment authorization is supported and cost-per-call pricing is acceptable.

## Known failure modes

- Payment not authorized or insufficient USDC balance — 402 Payment Required returned
- Invalid or missing 'amount' field — validation error
- Gateway service unavailable — 503 or timeout
- Malformed request body — 400 Bad Request
- Amount out of acceptable range — error response

## How this service works

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

## Output

Returns a JSON object containing the result of the currency conversion for the specified amount. The exact fields depend on the gateway's response but typically include the converted value and possibly metadata about the conversion.

## 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-converter-fff04ac0/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)