# 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 2026-10-13).

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

## Facts

- Endpoint: POST https://api.fastapi.online/f/fx/ang/mkd?utm_source=zero.xyz
- Price: $0.0002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ai-gateway-currency-conversion-endpoint-d63c7270
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WtLNldjW5w4YSbL1ccC3O

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-d63c7270 -d '<json body>'
```

Example prompt: Convert 250 units of the source currency using the x402 AI Gateway — charge the $0.0002 USDC micropayment and give me the converted result.

## When to prefer this

Choose this endpoint when you need a low-cost ($0.0002 USDC), pay-per-call currency conversion with no subscription required, and your agent already supports x402 micropayment flow on Base. Ideal for agents with infrequent or bursty conversion needs where a monthly-fee FX API is overkill.

## Known failure modes

- Payment not provided or insufficient USDC balance — 402 Payment Required response
- Invalid or unsupported currency pair — may return error or empty result
- Missing 'amount' field — defaults to 1 but may behave unexpectedly
- Network or gateway downtime — 5xx errors from self-hosted infrastructure
- Rate data unavailable — upstream exchange rate provider may be down

## 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 or exchange result. The exact schema is loosely typed (generic object), but expected to include the converted amount and possibly rate metadata.

## 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-d63c7270/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)