# x402 AI Gateway – Currency Amount Conversion

> x402 AI Gateway – Currency Amount Conversion is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0002/call, status unknown (last checked 2026-10-15).

Converts a specified amount of a source currency, using a self-hosted AI gateway protected by x402 USDC micropayment on Base.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/lsl?utm_source=zero.xyz
- Price: $0.0002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ai-gateway-currency-amount-conversion-4c229a95
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_E54V9O18i4o0fr2i0VeDO

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-conversion-4c229a95 -d '<json body>'
```

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

## When to prefer this

Choose this endpoint when you need a pay-per-call currency conversion via a self-hosted AI gateway that accepts x402 USDC micropayments on Base, and you want extremely low cost ($0.0002 per call). Ideal for high-frequency automated agents that need cheap, programmatic currency lookups without committing to a subscription-based FX API.

## Known failure modes

- Payment not attached or insufficient USDC micropayment — returns HTTP 402 Payment Required
- Invalid or missing 'amount' field — returns 400 Bad Request or validation error
- Server-side AI inference failure — returns 500 Internal Server Error
- Network timeout on self-hosted endpoint — connection refused or timeout
- Unsupported currency pair — may return empty or error 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 conversion result for the specified amount; exact fields depend on the server implementation but typically include the converted value and possibly exchange rate metadata.

## 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-conversion-4c229a95/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)