# GPT-5.5 Long-Output Chat Gateway (x402 USDC)

> GPT-5.5 Long-Output Chat Gateway (x402 USDC) is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.110876/call, status unknown (last checked 2026-09-13).

Provides GPT-5.5 chat completions optimized for long outputs via a GET endpoint, paid with x402 USDC on Base at $0.002134 per call

## Facts

- Endpoint: GET https://gpt55.558686.xyz/v1/paid/chat-long
- Price: $0.110876/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gpt-5-5-long-output-chat-gateway-x402-usdc-4ed550eb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_oomaaOmNEwPcjjx_rP3pl

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 gpt-5-5-long-output-chat-gateway-x402-usdc-4ed550eb
```

Example prompt: Give me a detailed GPT-5.5 explanation of how transformer attention mechanisms work, up to 4096 tokens, paid via x402 USDC on Base — I need a thorough answer, not a short summary.

## When to prefer this

Choose this endpoint when you need longer GPT-5.5 outputs (up to 4096 tokens) at a slightly higher per-call price than the compact tier ($0.002134 vs $0.0001), and you want token-metered or fixed-price x402 USDC payment on Base. Ideal for summaries, code explanations, and detailed answers that exceed compact-tier length limits.

## Known failure modes

- Insufficient USDC balance for x402 payment returns 402 Payment Required
- Input exceeding 700000 characters rejected
- max_tokens above 4096 rejected with validation error
- Missing required prompt/q/message parameter returns error
- Network or gateway timeout on long generations
- Invalid x402 payment header format causes authentication failure

## How this service works

OpenAI-compatible GPT-5.5 long-output paid chat over x402 Base USDC. Directory-friendly GET endpoint for longer agent answers, summaries, code explanations, and GPT-5.5 chat completions. Market benchmark: the latest local x402.direct sample found AI-like listing prices with p25 around $0.01 and median around $0.03 per call, while this gateway advertises a $0.110876 compact GPT-5.5 entry request, $0.110876 long-output GPT-5.5 requests, and $0.523889 true max-output GPT-5.5 requests. Pay up to $0.110876 per request with x402 USDC on Base. Exact fixed-price payment and upto token-metered payment are both accepted when clients support them; upto settlements use actual response usage, a 0.0001 minimum, and the selected tier price as the cap. Public paid calls are limited to 700000 input characters and 4096 output tokens.

## Output

An OpenAI-compatible JSON response containing an id, object type, model name, choices array with the generated text (up to 4096 tokens), and usage statistics reflecting actual token consumption.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "q": {
       "type": "string"
      },
      "prompt": {
       "type": "string"
      },
      "system": {
       "type": "string"
      },
      "message": {
       "type": "string"
      },
      "max_tokens": {
       "type": "integer",
       "maximum": 4096,
       "minimum": 1
      }
     },
     "additionalProperties": true
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "id",
      "object",
      "model",
      "choices"
     ],
     "properties": {
      "id": {
       "type": "string"
      },
      "model": {
       "type": "string"
      },
      "usage": {
       "type": "object"
      },
      "object": {
       "type": "string"
      },
      "choices": {
       "type": "array"
      }
     },
     "additionalProperties": true
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gpt-5-5-long-output-chat-gateway-x402-usdc-4ed550eb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gpt55.558686.xyz](https://www.zero.xyz/host/gpt55.558686.xyz/llms.txt)