# x402 AI Gateway – Currency Conversion Endpoint

> x402 AI Gateway – Currency Conversion Endpoint 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 one currency to another, gated by a USDC micropayment on Base via the x402 protocol.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/aoa/uyu?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-endpoint-8da1b8ce
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5lnvjBh7j3Olkiry5Gu0B

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-endpoint-8da1b8ce -d '<json body>'
```

Example prompt: Convert 250 USD to EUR for me — this uses the x402 micropayment gateway so it'll charge a tiny USDC fee per call.

## When to prefer this

Choose this endpoint when you need a pay-per-call, programmatic currency conversion without a subscription key, and you are already operating within an x402-compatible payment flow using USDC on Base. It is especially suitable for AI agents that handle their own micropayments autonomously.

## Known failure modes

- Payment not included or rejected — 402 Payment Required response; agent must attach valid USDC micropayment on Base
- Invalid or missing amount field — may return a 422 or 400 validation error
- Unsupported currency pair — gateway may return an error if the source/target currencies are not recognized
- Network or gateway downtime — 5xx error from the self-hosted server
- Insufficient payment amount — payment below $0.0002 USDC threshold rejected

## 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 converted currency value for the specified amount. The exact fields depend on the gateway implementation, but typically includes the result of 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-conversion-endpoint-8da1b8ce/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)