# GPT-5 Nano via x402 Gateway

> GPT-5 Nano via x402 Gateway is a paid API for AI agents from x402-gateway-production.up.railway.app, paid per call via x402, $0.002000/call, status unknown (last checked 2026-09-14).

Calls OpenAI's GPT-5 Nano model — the cheapest GPT-5 tier — via a pay-per-call x402 gateway for high-volume, cost-sensitive agent tasks

## Facts

- Endpoint: POST https://x402-gateway-production.up.railway.app/api/llm/gpt-5-nano
- Price: $0.002000/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-gateway-production-up-railway-app-9c4aa976
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wtRcbbwzv7TPs2q3tfns2

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-gateway-production-up-railway-app-9c4aa976 -d '<json body>'
```

Example prompt: Use the cheapest GPT-5 model to summarize the following product review in two sentences: 'The battery life is amazing and the screen is gorgeous, but the camera quality disappointed me and setup took forever.'

## When to prefer this

Choose this endpoint when cost-per-call is the primary concern and you need GPT-5 quality at the lowest available tier — ideal for high-volume automation, bulk classification, summarization pipelines, or any agent loop making many LLM calls. Prefer over GPT-4o or Claude endpoints when the task is straightforward and does not require advanced reasoning or multimodal input.

## Known failure modes

- Payment not included or insufficient USDC — 402 Payment Required
- Prompt too long for model context window — 400 Bad Request
- Model temporarily unavailable on gateway — 503 Service Unavailable
- Malformed request body — 400 with validation error
- Rate limit exceeded on gateway — 429 Too Many Requests

## How this service works

OpenAI's cheapest GPT-5 tier — ultra-affordable for high-volume agent tasks

## Output

A generated text response from GPT-5 Nano — typically a completion, answer, summary, or classification based on the input prompt, returned as a JSON payload with the model output.

## Example request

```json
{
 "messages": [
  {
   "role": "user",
   "content": "Summarize the following product review in two sentences: 'The battery life is amazing and the screen is gorgeous, but the camera quality disappointed me and setup took forever.'"
  }
 ],
 "max_tokens": 100
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-gateway-production-up-railway-app-9c4aa976/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-gateway-production.up.railway.app](https://www.zero.xyz/host/x402-gateway-production.up.railway.app/llms.txt)