# 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 USDC micropayment on Base before executing.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/mru?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-9ecaa6db
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pUzN9XGTM38c3FNNWlyia

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-9ecaa6db -d '<json body>'
```

Example prompt: Convert 50 units of the source currency for me using the x402 gateway — the amount I want to convert is 50.

## When to prefer this

Choose this endpoint when you need a low-cost ($0.0002 USDC), pay-per-call currency conversion without committing to a subscription, and your agent already supports the x402 micropayment protocol on Base. Best for lightweight, infrequent conversions where a dedicated FX API subscription is overkill.

## Known failure modes

- Payment not provided or rejected — 402 Payment Required returned before execution
- Invalid or missing amount field — 422 Unprocessable Entity
- Upstream currency data unavailable — 503 or empty result
- Malformed request body — 400 Bad Request
- Micropayment insufficient — gateway rejects and returns 402

## 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 conversion result for the specified amount; exact output fields depend on the gateway's current implementation but typically include the converted value or exchange details.

## 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-9ecaa6db/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)