# 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 from one currency to another, accessible via micropayment-gated AI gateway using USDC on Base.

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/kyd?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-270aec8a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KWEU4gY6Yx-985c6gkBML

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-270aec8a -d '<json body>'
```

Example prompt: Convert 250 units of currency using the x402 micropayment-gated gateway and give me the result.

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call currency conversion capability within an x402-compatible micropayment workflow, especially when operating on Base/USDC infrastructure. It is well-suited for AI agents that need occasional FX lookups without committing to a subscription-based FX API. Avoid if you need detailed exchange rate metadata, historical rates, or multi-pair batch conversions, as the schema is minimal.

## Known failure modes

- Payment not completed or rejected — endpoint returns HTTP 402 requiring USDC micropayment before proceeding
- Invalid or missing amount input — may return a validation error or default to amount=1
- Upstream gateway unavailable — returns 5xx server error
- Malformed request body — returns 4xx with schema error
- Insufficient USDC balance or wallet not connected — payment step fails before execution

## 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 result of the currency conversion computation for the specified input amount. The exact fields are unspecified beyond the generic object schema, but expected to include the converted value or equivalent 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-conversion-endpoint-270aec8a/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)