# 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 via a self-hosted AI gateway, gated by an x402 USDC micropayment on Base.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/aoa/vnd?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-096c727c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_C-ViA5YZ61N6LlfFdqf2o

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-096c727c -d '<json body>'
```

Example prompt: Can you convert 250 US dollars to Japanese yen using the x402 AI Gateway — I need the converted amount now and it's okay to make the micropayment.

## When to prefer this

Choose this endpoint when you need a micropayment-gated, self-hosted currency conversion that integrates with the x402 payment protocol on Base/USDC. It is appropriate for agents that already have x402 payment capabilities and want a lightweight, per-call-priced conversion without committing to a subscription-based FX API.

## Known failure modes

- Payment not provided or insufficient — returns HTTP 402 requiring x402 USDC micropayment before execution
- Invalid or unsupported currency codes — returns an error or empty result
- Amount field missing or non-numeric — may default to 1 or return a validation error
- Network or gateway downtime on the self-hosted server — returns 5xx error
- x402 facilitator or Base network congestion — payment confirmation delay causing timeout

## 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 amount for the specified source amount and currency pair, provided the x402 USDC micropayment on Base is successfully processed.

## 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-096c727c/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)