# GPT-5.2 via x402 Gateway

> GPT-5.2 via x402 Gateway is a paid API for AI agents from x402-gateway-production.up.railway.app, paid per call via x402, $0.08/call, status unknown (last checked 2026-09-14).

Calls OpenAI's GPT-5.2 flagship model for top-tier reasoning, coding, and multimodal tasks via a pay-per-call x402 gateway

## Facts

- Endpoint: POST https://x402-gateway-production.up.railway.app/api/llm/gpt-5.2
- Price: $0.08/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-ab0e834e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_uajSMm7YT6qfZbsBcy2Gq

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-ab0e834e -d '<json body>'
```

Example prompt: Use OpenAI's GPT-5.2 flagship model to analyze this business proposal and give me a detailed breakdown of its strengths, weaknesses, and financial risks — I need the most capable reasoning you can get.

## When to prefer this

Choose this endpoint when you need OpenAI's most capable GPT-5.2 model for complex reasoning, hard coding tasks, or multimodal inputs, and you want a pay-per-call model via x402 without managing OpenAI API keys or subscriptions directly. Prefer over cheaper GPT-5 tiers when task quality is paramount.

## Known failure modes

- Payment not included or insufficient USDC — returns 402 Payment Required
- Malformed request body — returns 400 Bad Request
- Model overloaded or upstream OpenAI outage — returns 503 or 502
- Context window exceeded — returns 400 with token limit error
- Invalid API key or auth — returns 401

## How this service works

OpenAI's latest flagship model — top-tier reasoning, coding, and multimodal capabilities

## Output

Returns a high-quality text (or multimodal) response generated by GPT-5.2, including reasoning, code, analysis, or other content as requested. Response quality reflects OpenAI's top-tier flagship model capabilities.

## Example request

```json
{
 "model": "gpt-5.2",
 "messages": [
  {
   "role": "user",
   "content": "Analyze the strengths and weaknesses of a hypothetical SaaS business model for a project management tool targeting small teams."
  }
 ],
 "max_tokens": 1000,
 "temperature": 0.7
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-gateway-production-up-railway-app-ab0e834e/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)