# 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 by an x402 USDC micropayment on Base before executing.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/ghs?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-6179c487
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zm80k-ikWDb7Pa5km24JG

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-6179c487 -d '<json body>'
```

Example prompt: Can you convert 250 of my source currency using the x402 AI gateway? It requires a tiny USDC micropayment on Base per call — go ahead and authorize that.

## When to prefer this

Choose this endpoint when you need a pay-per-call, micropayment-gated currency amount conversion that settles on-chain via USDC on Base. It is especially suitable for AI agents that natively support x402 payment flows and need lightweight, serverless-style computation without API key management. Prefer alternatives for high-volume batch conversions or when on-chain payment overhead is undesirable.

## Known failure modes

- Payment not provided or rejected — 402 Payment Required response blocking execution
- Invalid or missing amount field — may default to 1 or return a validation error
- Upstream gateway unavailable — 502/503 if self-hosted inference server is down
- Malformed request body — 422 Unprocessable Entity if schema is violated
- Insufficient USDC balance on Base for micropayment — payment gateway rejects the transaction

## 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 computation. The exact fields returned are not fully documented (response schema is a generic object), but expected to include the converted amount or equivalent value for the input amount provided.

## 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-6179c487/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)