# GPT-5.4 via x402 Gateway

> GPT-5.4 via x402 Gateway is a paid API for AI agents from x402-gateway-production.up.railway.app, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15, last successful call 2026-06-17).

Calls OpenAI's GPT-5.4 flagship model with 1M context window and computer-use capability via a pay-per-call x402 payment gateway

## Facts

- Endpoint: POST https://x402-gateway-production.up.railway.app/api/llm/gpt-5.4
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Last successful call: 2026-06-17
- Success rate: 40% of calls made through Zero
- Activations on Zero: 10
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-gateway-production-up-railway-app-a45ae2a0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wJ4Ws1ARWxktgp_Hp6YXx

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-a45ae2a0 -d '<json body>'
```

Example prompt: Use GPT-5.4 — OpenAI's unified flagship with 1M context and computer-use support — to analyze this 800-page contract and summarize all indemnification clauses, then draft a redline memo highlighting the top 5 risks.

## When to prefer this

Choose this endpoint when you need OpenAI's most capable and unified model (GPT-5.4) for complex reasoning, long-context (up to 1M tokens), computer-use tasks, or top-tier multimodal performance, and you want pay-per-call access via x402 without managing an OpenAI subscription or API key directly.

## Known failure modes

- Insufficient USDC balance for x402 payment — returns 402 Payment Required
- Invalid or malformed prompt payload — returns 400 Bad Request
- Model unavailable or overloaded — returns 503 Service Unavailable
- Context length exceeds 1M tokens — returns 400 with token limit error
- Network timeout for long generation requests — returns 504 Gateway Timeout

## How this service works

OpenAI's unified flagship model — 1M context, computer use, top-tier across all tasks

## Output

Returns the model's generated text response to the provided prompt or messages, leveraging GPT-5.4's top-tier reasoning, vision, and extended 1M-token context capabilities.

## Example request

```json
{
 "model": "gpt-5.4",
 "messages": [
  {
   "role": "user",
   "content": "Summarize the key features and capabilities of artificial intelligence in healthcare applications."
  }
 ],
 "max_tokens": 500,
 "temperature": 0.7
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-gateway-production-up-railway-app-a45ae2a0/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)