# 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 execution.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/aoa/yer?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-86ea7940
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fpOiKAzT3woTyswuj0nyw

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-86ea7940 -d '<json body>'
```

Example prompt: Convert 250 units of source currency using the x402 AI gateway — just pass the amount as 250 and give me back the converted result.

## When to prefer this

Choose this endpoint when you need a low-cost, per-call currency conversion with programmatic micropayment gating via x402 on Base (USDC). Ideal for agents that need occasional FX lookups without a subscription, or for workflows that benefit from pay-per-use pricing at $0.0002 per call. Less suitable if you need guaranteed SLA, detailed currency metadata, or bulk conversions.

## Known failure modes

- Missing or failed x402 USDC micropayment results in 402 Payment Required before execution
- Invalid or missing 'amount' field may return a 422 validation error
- Downstream currency data unavailable may return a 500 or empty result
- Insufficient USDC balance on Base network blocks the call
- Malformed request body returns a 400 Bad Request

## 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 conversion for the specified amount; exact fields depend on the endpoint implementation but expected to include the converted value or rate information.

## 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-86ea7940/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)