# Low-Price GPT-5.5 x402 API Gateway – Max-Output Chat Completions

> Low-Price GPT-5.5 x402 API Gateway – Max-Output Chat Completions is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.523889/call, status unknown (last checked 2026-10-22).

Calls GPT-5.5 chat completions with up to 128,000 output tokens via a pay-per-use x402 USDC micropayment gateway at $0.066667 per request

## Facts

- Endpoint: GET https://gpt55.558686.xyz/v1/chat/completions/max-output?utm_source=zero.xyz
- Price: $0.523889/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/low-price-gpt-5-5-x402-api-gateway-max-output-chat-completions-c60ab694
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Y81q9-u9-wdcYsE5hgYxt

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 low-price-gpt-5-5-x402-api-gateway-max-output-chat-completions-c60ab694
```

Example prompt: Ask GPT-5.5 to write a detailed 10,000-word technical report on quantum computing advances, using the system prompt 'You are an expert scientist' and allow up to 20000 output tokens — pay per use, no subscription needed.

## When to prefer this

Choose this endpoint when you need GPT-5.5 completions with very long outputs (up to 128k tokens), want to pay per request in USDC without a subscription, or are building an agent that needs OpenAI-compatible responses via the x402 micropayment protocol on Base. It is priced higher than the compact endpoint ($0.066667) because it supports maximum output length — prefer it for document generation, long reasoning chains, or extensive content creation tasks.

## Known failure modes

- Payment failure: insufficient USDC balance or x402 payment rejection returns a 402 error
- Invalid model parameter: only 'gpt-5.5' is accepted; other values may be rejected
- Exceeding max_tokens limit of 128,000 causes a validation error
- Missing required 'input' query parameter returns a 400 bad request
- Network or gateway timeout for very long completions
- Rate limiting if too many requests are sent in rapid succession

## How this service works

GET quote and query-parameter variant for the true max-output OpenAI-compatible GPT-5.5 chat completion alias. Use this for directory health checks, wallets, and simple agent clients that validate x402 payment requirements before issuing a paid call. 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 $0.523889 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 128000 output tokens. This alias supersedes stale directory entries that indexed the older /v1/chat/completions/max URL with an incorrect price.

## Output

Returns an OpenAI-compatible JSON chat completion object with an assistant message, finish reason, token usage breakdown (prompt, completion, total), model name ('gpt-5.5'), and a unique completion ID. The response supports up to 128,000 output tokens for large-output tasks.

## 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"
      },
      "input": {
       "type": "string"
      },
      "model": {
       "enum": [
        "gpt-5.5",
        "gpt-5.4-mini"
       ],
       "type": "string"
      },
      "prompt": {
       "type": "string"
      },
      "system": {
       "type": "string"
      },
      "message": {
       "type": "string"
      },
      "max_tokens": {
       "type": "integer",
       "maximum": 128000,
       "minimum": 1
      },
      "system_prompt": {
       "type": "string"
      },
      "max_output_tokens": {
       "type": "integer",
       "maximum": 128000,
       "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/low-price-gpt-5-5-x402-api-gateway-max-output-chat-completions-c60ab694/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)