# 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 2026-10-16).

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/mur?utm_source=zero.xyz
- Price: $0.0002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ai-gateway-currency-conversion-endpoint-58a9f49b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fA0sySqPFMJmPdEtqaPrX

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-58a9f49b -d '<json body>'
```

Example prompt: Convert 250 units of the source currency using the x402-gated FX conversion endpoint — it costs $0.0002 USDC per call and runs on Base.

## When to prefer this

Prefer this endpoint when you need a very cheap ($0.0002 USDC per call), pay-per-use currency conversion that is gated by an x402 micropayment on the Base network, especially in autonomous agent pipelines where automated USDC payments are already supported. It is well-suited for high-volume, low-cost FX lookups where you want to avoid subscription fees.

## Known failure modes

- Payment not received or insufficient USDC micropayment triggers 402 Payment Required before any computation is attempted
- Invalid or missing 'amount' parameter may cause a 400 Bad Request or unspecified error
- Service unavailability of the self-hosted gateway returns 5xx errors
- Ambiguous source/target currency may yield unexpected or null conversion results
- Network timeouts on the Base blockchain payment layer may delay or fail the call

## 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. The exact fields in the response object are not formally specified beyond the top-level object wrapper.

## 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-58a9f49b/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)