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

> Low-Price GPT-5.5 x402 API Gateway – Long Output Chat Completions is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.110876/call, status unknown (last checked 2026-10-22).

Generates long-form GPT-5.5 chat completions via a GET request, paid per-call in USDC over the x402 protocol on Base

## Facts

- Endpoint: GET https://gpt55.558686.xyz/v1/chat/completions/long?utm_source=zero.xyz
- Price: $0.110876/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-long-output-chat-completions-3a1f494d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xj9NZvXpCVMyONNW8OjGw

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-long-output-chat-completions-3a1f494d
```

Example prompt: Ask GPT-5.5 to write me a detailed, long-form explanation of how transformer attention mechanisms work — use up to 4096 output tokens and set the system prompt to 'You are an expert ML educator.'

## When to prefer this

Choose this endpoint when you need long-form GPT-5.5 completions (up to 4096 output tokens) and want to pay per call in USDC via x402 with no subscription required. Prefer this over the compact/short endpoint when you expect verbose answers, detailed explanations, or lengthy generated content. Prefer over official OpenAI API when you need micropayment-native, crypto-native access without API key management.

## Known failure modes

- Payment not received or insufficient USDC balance — x402 payment failure, request rejected
- Invalid or missing 'input' query parameter — 400 Bad Request
- max_tokens or max_output_tokens out of range (must be 1–4096) — validation error
- Model enum mismatch (only 'gpt-5.5' accepted) — request rejected
- Upstream GPT-5.5 API unavailability — 502 or 503 error from gateway
- Rate limiting if too many concurrent calls are attempted from same address

## How this service works

GET quote and query-parameter variant for the long-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 $0.110876 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

Returns an OpenAI-compatible JSON chat completion object including the assistant's generated message content, model name (gpt-5.5), finish reason, completion ID, and token usage breakdown (prompt, completion, and total tokens).

## 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": 4096,
       "minimum": 1
      },
      "system_prompt": {
       "type": "string"
      },
      "max_output_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/low-price-gpt-5-5-x402-api-gateway-long-output-chat-completions-3a1f494d/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)