# 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 2026-10-10).

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/kgs?utm_source=zero.xyz
- Price: $0.0002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ai-gateway-currency-amount-converter-c016725a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_gKKkSTNV_3Ovosvn4tOcp

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-c016725a -d '<json body>'
```

Example prompt: Convert 250 units of USD to EUR for me — I need the converted amount back using that self-hosted x402 micropayment gateway.

## When to prefer this

Choose this endpoint when you need a lightweight, self-hosted, pay-per-call currency conversion that operates within the x402 micropayment protocol on Base (USDC). It is ideal for agents that already have x402 payment capability and want to avoid subscription-based FX APIs. At $0.0002 per call it is extremely cheap for low-volume or on-demand conversion needs.

## Known failure modes

- 402 Payment Required if the USDC micropayment on Base is not provided or fails
- Invalid or missing amount field results in a validation error
- Unsupported currency pair may return an error or empty result
- Network timeout or gateway unavailability
- Malformed request body causing a 422 Unprocessable Entity 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 amount conversion; the exact fields depend on the gateway implementation 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-c016725a/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)