Pricing and Fees

ZenMux uses a transparent billing system to ensure every call is precisely measured and billed. Pricing varies by model, and the same model may be priced differently across providers.

View Pricing

You can view provider-specific pricing on the model details page. Each provider displays a detailed pricing schedule, including costs for input tokens, output tokens, and special features.

Billing Items

The billing items include the following types:

Billing Item	Description
prompt	Cost for processing input prompts
completion	Cost for model-generated outputs
image	Cost for image processing or generation
request	Base fee per API request
web_search	Fee for invoking web search
input_cache_read	Cost for cache read operations
input_cache_write	Cost for cache write operations
input_cache_write_5_min	Cost for 5-minute cache write operations
input_cache_write_1_h	Cost for 1-hour cache write operations
internal_reasoning	Cost for internal reasoning computation

Billing Precision Guarantee

We ensure that every call is precisely metered and billed. You can review detailed cost breakdowns in the console page.

Viewing Cost Details

Console Activity Page

On the console's Activity page, you can view cost details for all API calls, including the specific cost of each call, token usage, call time, and more.

Click a specific call record to view a more detailed cost breakdown:

Raw Meta Information

In addition to the console, you can inspect the raw Meta information returned by the API to understand call costs. Below is a complete sample payload:

Cost Details JSON Example

{
  "generationId": "2534CCEDTKJR00217635",
  "accountId": "2533AC0Q5MIe14613672",
  "apiKeyId": "2534AKkA4Nqn14642786",
  "authorSlug": "anthropic",
  "modelSlug": "anthropic/claude-sonnet-4",
  "providerSlug": "anthropic",
  "endpointSlug": "anthropic/ahtnropic_endpoint",
  "appId": null,
  "createdAt": "2025-08-22T02:49:18.000+00:00",
  "generationTime": 3298,
  "latency": 2177,
  "moderationLatency": 2169,
  "streamed": true,
  "cancelled": false,
  "tokensPrompt": 16527,
  "tokensCompletion": 95,
  "tokensReasoning": 0,
  "throughput": "28.81",
  "nativeTokensPrompt": 16527,
  "nativeTokensCompletion": 95,
  "nativeTokensReasoning": 0,
  "nativeFeeTokens": {
    "input_cache_write_5_min": 0,
    "completion": 95,
    "input_cache_read": 0,
    "input_cache_write_1_h": 0,
    "prompt": 16527
  },
  "nativeTokens": {
    "completion_tokens": 95,
    "prompt_tokens": 16527,
    "total_tokens": 16622,
    "completion_tokens_details": { "reasoning_tokens": 0 },
    "prompt_tokens_details": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0,
      "cached_tokens": 0
    }
  },
  "finishReason": "tool_calls",
  "nativeFinishReason": "tool_calls",
  "origin": null,
  "providerResponses": null,
  "providerApiKeyId": "2533PCgBu07N14613665",
  "byok": false,
  "originAmount": "0.051006",
  "billAmount": "0.051006",
  "discountAmount": "0",
  "realAmount": "0.051006",
  "nonpaymentAmount": "0",
  "ratingResponses": {
    "billAmount": 0.051006,
    "discountAmount": 0,
    "originAmount": 0.051006,
    "priceVersion": "0.0.3",
    "ratingDetails": [
      {
        "billAmount": 0,
        "discountAmount": 0,
        "feeItemCode": "input_cache_write_5_min",
        "originAmount": 0,
        "rate": 3.75
      },
      {
        "billAmount": 0.001425,
        "discountAmount": 0,
        "feeItemCode": "completion",
        "originAmount": 0.001425,
        "rate": 15
      },
      {
        "billAmount": 0,
        "discountAmount": 0,
        "feeItemCode": "input_cache_read",
        "originAmount": 0,
        "rate": 0.3
      },
      {
        "billAmount": 0,
        "discountAmount": 0,
        "feeItemCode": "input_cache_write_1_h",
        "originAmount": 0,
        "rate": 6
      },
      {
        "billAmount": 0.049581,
        "discountAmount": 0,
        "feeItemCode": "prompt",
        "originAmount": 0.049581,
        "rate": 3
      }
    ],
    "serviceCode": "anthropic#anthropic/ahtnropic_endpoint#anthropic/claude-sonnet-4"
  },
  "requestRetryTimes": 0,
  "finalRetry": true,
  "billStatus": 0,
  "bizHour": "2025082202",
  "bizDate": "20250822",
  "bizMonth": "202508",
  "bizWeek": "202534",
  "source": "itboxroutercore",
  "ext": { "traceId": "21d5e62d17558309613841043942", "requestSuccess": true },
  "model": "Anthropic: Claude Sonnet 4"
}

Key Cost Fields

Understanding the key cost fields in the Meta information helps you analyze and manage call costs:

Field Name	Data Type	Description
originAmount	string	Original amount (before billing adjustments)
billAmount	string	Billed amount
discountAmount	string	Discount amount
realAmount	string	Final payable amount
ratingDetails	array	Detailed cost breakdown by billing item, including per-unit rates

Cost Calculation

The final payable amount is calculated as: realAmount = billAmount - discountAmount

Each ratingDetails entry includes the itemized cost and per-unit rate for that billing item.