# 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 down (last checked 2026-10-17).

Converts a specified amount of one currency to another, gated by an x402 USDC micropayment on Base before execution.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/kwd?utm_source=zero.xyz
- Price: $0.0002/call
- Payment: x402
- Status: down
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ai-gateway-currency-conversion-endpoint-dfbc9357
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lSSWUQ-RassQOJRhgbdu2

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-dfbc9357 -d '<json body>'
```

Example prompt: Convert 250 USD to EUR for me using the x402 micropayment gateway — just pay the $0.0002 USDC fee and give me the result.

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call currency conversion capability and are already operating within an x402-compatible payment infrastructure using USDC on Base. It is ideal for agents that handle small, infrequent conversions where a subscription-based forex API is overkill, or when testing x402 micropayment-gated workflows in a self-hosted environment.

## Known failure modes

- Payment not included or insufficient — server returns HTTP 402 requiring x402 USDC micropayment on Base before proceeding
- Invalid or unsupported currency codes — endpoint may return an error or empty result
- Amount field missing or non-numeric — schema validation error
- Network or server downtime on the self-hosted instance — connection timeout or 5xx error
- Stale or unavailable exchange rate data — result may be outdated or endpoint returns error

## How this service works

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

## Output

Returns an object containing the converted currency value for the specified amount, based on current exchange rates. The exact response fields depend on the server implementation but typically include the converted amount and possibly the rate used.

## 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-dfbc9357/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)