# 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).

Runs a GPT-5.5 chat completion request via x402 USDC micropayment on Base, supporting up to 128,000 output tokens per call at $0.066667

## Facts

- Endpoint: GET https://gpt55.558686.xyz/v1/chat/completions/max?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-1bd30af9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_opsMVvCOxatv6lWyJvEci

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-1bd30af9
```

Example prompt: Ask GPT-5.5 to write a detailed 3,000-word blog post about the future of decentralized AI — use a system prompt that says 'You are a tech journalist' and allow up to 4000 output tokens.

## When to prefer this

Choose this endpoint when you need GPT-5.5 completions with large output (up to 128k tokens) and want to pay per-call in USDC via x402 on Base without a subscription. Prefer over the compact variant when response length is expected to be substantial. Use when an OpenAI-compatible response schema is required and crypto micropayment is acceptable or preferred.

## Known failure modes

- Payment not received or x402 USDC transaction on Base fails — returns 402 Payment Required
- Invalid or missing input query parameters — returns 400 Bad Request
- Model overload or upstream OpenAI rate limit — returns 503 or 429
- max_output_tokens exceeds 128000 — rejected by schema validation
- Network timeout on long high-token completions — returns 504 Gateway Timeout
- Malformed JSON response if upstream provider is degraded

## How this service works

GET quote and query-parameter variant for the true max-output OpenAI-compatible GPT-5.5 chat completion endpoint. 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.

## Output

Returns an OpenAI-compatible JSON chat completion object containing the assistant's message content, finish reason, token usage (prompt, completion, total), completion ID, and model name (gpt-5.5). The choices array holds the generated text under choices[0].message.content.

## 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-1bd30af9/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)