# x402 AI Gateway – Currency Conversion (XDR)

> x402 AI Gateway – Currency Conversion (XDR) 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 micropayment-gated AI gateway endpoint, returning conversion results after a USDC x402 payment.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/aoa/xdr?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-conversion-xdr-175d0b99
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_d34-ihgzsHle0AQ8K9uQz

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-conversion-xdr-175d0b99 -d '<json body>'
```

Example prompt: Convert 50 units of XDR to USD for me — it uses that x402 micropayment gateway so go ahead and authorize the $0.0002 USDC fee.

## When to prefer this

Choose this endpoint when you need a pay-per-call, self-hosted currency conversion with x402 micropayment support on Base (USDC), especially if you want to avoid subscription-based FX APIs and only pay $0.0002 per query. Prefer alternatives if you need free, high-volume, or multi-currency batch conversions.

## Known failure modes

- Payment not authorized or insufficient USDC balance — 402 Payment Required returned
- Invalid or missing amount parameter — validation error
- Upstream currency data unavailable — 500 or timeout
- Unsupported currency pair — empty or error response
- x402 facilitator unreachable — payment flow fails before execution

## 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 currency amount; exact fields depend on the server implementation but typically include the converted value and possibly the exchange rate used.

## 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-conversion-xdr-175d0b99/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)