# 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 2026-10-12).

Converts a specified amount of a source currency, gated behind an x402 micropayment in USDC on Base before execution.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/mnt?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-conversion-44a33ec5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0hiQEHdEi9N9cLul3Fv7M

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-44a33ec5 -d '<json body>'
```

Example prompt: Convert 250 units of my source currency using the x402-gated gateway — the default amount is 1 if I don't specify.

## When to prefer this

Choose this endpoint when you need a lightweight, micropayment-gated currency conversion call on a self-hosted infrastructure and are already set up to handle x402 USDC payments on Base. Useful for agents that need cost-controlled, per-call currency lookups without committing to a subscription API.

## Known failure modes

- Payment not provided or rejected — 402 Payment Required returned before execution
- Invalid or missing amount field — server may return 400 or default to 1
- Service unavailable on self-hosted infrastructure — 503 or timeout
- Unsupported currency pair — may return empty or error object
- Malformed request body — 422 Unprocessable Entity

## How this service works

Self-hosted AI API gateway. Expensive endpoints require an x402 micropayment (USDC on Base) before executing.

## Output

A JSON object containing the result of the currency conversion for the specified amount; exact fields depend on the server implementation but typically include the converted value or exchange result.

## 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-44a33ec5/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)