# GPT-5.5 Sub2API Metered Invoice Generator

> GPT-5.5 Sub2API Metered Invoice Generator is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.066667/call, status unknown (last checked 2026-09-14).

Generates a buyer-ready postpaid invoice JSON for GPT-5.5 usage by computing costs across input, output, cache creation, cache read, image output, service tier, long-context, and rate multiplier fields using the read-only sub2api pricing formula.

## Facts

- Endpoint: POST https://gpt55.558686.xyz/v1/tools/sub2api-official-metered-invoice
- Price: $0.066667/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gpt-5-5-sub2api-metered-invoice-generator-2735cd28
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_E34gdpZXzWKl8sVqMC3Se

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-sub2api-metered-invoice-generator-2735cd28 -d '<json body>'
```

Example prompt: Calculate my GPT-5.5 invoice for a priority-tier request with 12000 input tokens, 800 output tokens, 3000 cache creation tokens, 1500 cache read tokens, and 200 image output tokens using a rate multiplier of 1.2 — give me the full machine-readable invoice breakdown.

## When to prefer this

Use this endpoint when you need a deterministic, read-only cost calculation for GPT-5.5 usage across all pricing dimensions (input, output, caching, image, tier, multiplier) without triggering any sub2api state changes — ideal for usage-metered x402 billing pipelines that need machine-readable invoice JSON after a completion call.

## Known failure modes

- Invalid token counts (negative integers) return validation errors
- Unsupported service_tier enum value returns 422
- Exceeding 700000 input characters returns a limit-exceeded error
- Missing required token fields may result in zero-cost invoice or error
- Payment of less than $0.066667 USDC via x402 results in 402 rejection

## How this service works

GPT-5.6 Luna API Base USDC and OpenAI-compatible x402 chat: one request for $0.00293, paid by browser wallet or a quote-first agent fallback.

## Output

Returns a machine-readable invoice JSON containing line-item costs for each token category (input, output, cache creation, cache read, image output), service tier adjustments, long-context surcharges, rate multiplier applied totals, and a final total charge in USD.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tier": {
   "enum": [
    "default",
    "flex",
    "priority"
   ],
   "type": "string"
  },
  "model": {
   "type": "string",
   "maxLength": 80
  },
  "modelId": {
   "type": "string",
   "maxLength": 80
  },
  "model_id": {
   "type": "string",
   "maxLength": 80
  },
  "requestId": {
   "type": "string",
   "maxLength": 160
  },
  "request_id": {
   "type": "string",
   "maxLength": 160
  },
  "serviceTier": {
   "enum": [
    "default",
    "flex",
    "priority"
   ],
   "type": "string"
  },
  "input_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "promptTokens": {
   "type": "integer",
   "minimum": 0
  },
  "service_tier": {
   "enum": [
    "default",
    "flex",
    "priority"
   ],
   "type": "string"
  },
  "contextTokens": {
   "type": "integer",
   "minimum": 0
  },
  "output_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "prompt_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "context_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "rateMultiplier": {
   "type": "number",
   "minimum": 0
  },
  "cacheReadTokens": {
   "type": "integer",
   "minimum": 0
  },
  "rate_multiplier": {
   "type": "number",
   "minimum": 0
  },
  "completionTokens": {
   "type": "integer",
   "minimum": 0
  },
  "cache_read_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "completion_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "imageOutputTokens": {
   "type": "integer",
   "minimum": 0
  },
  "cacheCreationTokens": {
   "type": "integer",
   "minimum": 0
  },
  "cached_input_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "image_output_tokens": {
   "type": "integer",
   "minimum": 0
  },
  "cache_creation_tokens": {
   "type": "integer",
   "minimum": 0
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "tool": "sub2apiOfficialMeteredInvoice",
  "summary": "Generated text."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gpt-5-5-sub2api-metered-invoice-generator-2735cd28/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)