# x402 AI Gateway — Currency Conversion

> x402 AI Gateway — Currency Conversion is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0002/call, status unknown (last checked 2026-10-11).

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

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/lak?utm_source=zero.xyz
- Price: $0.0002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ai-gateway-currency-conversion-441df938
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_G5aSL2w_dR2H1WnXcZvta

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-441df938 -d '<json body>'
```

Example prompt: Convert 250 USD to EUR for me — use the x402-gated currency conversion endpoint on fastapi.online and deduct the $0.0002 USDC fee automatically.

## When to prefer this

Choose this endpoint when you need a quick, cheap currency conversion via a self-hosted gateway and your agent stack already supports x402 micropayment flows on Base (USDC). At $0.0002 per call it is cost-effective for high-frequency conversions. Prefer it when you want to avoid centralized FX API key management and instead use crypto-native pay-per-use access.

## Known failure modes

- Payment not attached or insufficient USDC balance returns HTTP 402 Payment Required
- Invalid or unsupported currency codes may return an error or empty result
- Malformed amount (e.g. negative or non-numeric) may cause a 422 Unprocessable Entity
- Service unavailability due to self-hosted infrastructure downtime returns 5xx
- Missing amount field may default to 1 or return a validation error

## 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 value for the specified amount, computed at current exchange rates. The exact response schema is open-ended but expected to include the result of the conversion.

## 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-441df938/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)