# 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 using a self-hosted AI gateway protected by x402 USDC micropayment on Base.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/aoa/zwg?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-cb6af11d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RPphxTeQUZyKdh1to2LZy

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-cb6af11d -d '<json body>'
```

Example prompt: Convert 250 units of source currency using the x402 AI gateway — charge the $0.0002 USDC micropayment and give me back the conversion result.

## When to prefer this

Choose this endpoint when you need a pay-per-call currency conversion via a self-hosted AI gateway with x402 USDC micropayment on Base, particularly in agentic workflows where you want minimal per-call cost ($0.0002 USDC) and no subscription overhead. Prefer this over traditional FX APIs when operating within an x402-compatible payment infrastructure.

## Known failure modes

- Payment not made or x402 micropayment rejected — endpoint returns 402 Payment Required
- Invalid or missing 'amount' field — endpoint returns validation error
- Amount is zero or negative — may return an error or unexpected result
- Gateway overloaded or self-hosted server unavailable — connection timeout or 503
- Unsupported currency pair — may return an empty or 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 with the conversion result for the specified currency amount. The exact fields depend on the gateway's AI model response, but typically includes 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-conversion-cb6af11d/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)