# 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 via a self-hosted AI gateway endpoint gated by x402 micropayment (USDC on Base).

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/nio?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-9fb77906
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mXSkRbSKEOMg6q0BiLf1y

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-9fb77906 -d '<json body>'
```

Example prompt: Convert 250 units of my source currency using the x402-gated AI gateway — I'm okay paying the $0.0002 USDC micropayment per call.

## When to prefer this

Choose this endpoint when you need a per-call, pay-as-you-go currency/amount computation gated by x402 micropayments on Base (USDC), and you are already operating within an x402-compatible payment flow. Suitable for AI agents that can autonomously authorize tiny USDC payments. Not ideal if you need free, high-volume, or SLA-guaranteed conversion.

## Known failure modes

- 402 Payment Required — x402 micropayment not provided or insufficient USDC balance on Base
- Invalid amount — non-numeric or missing amount field returns validation error
- Gateway timeout — self-hosted server may be unavailable or slow
- Unknown or unsupported currency pair — gateway may return empty or error response
- Network error reaching api.fastapi.online

## 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 gateway's runtime response, but typically includes the converted value or computation output.

## 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-9fb77906/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)