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@reaatech/llm-cache-cost-tracker

pending npm

Calculates LLM request costs and cache savings using a built-in database of pricing for over 40 models. It provides a `CostCalculator` class that implements the `CostCalculatorLike` interface for direct integration with `@reaatech/llm-cache`.

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@reaatech/llm-cache-cost-tracker

npm version License: MIT CI

Status: Pre-1.0 — APIs may change in minor versions. Pin to a specific version in production.

Cost calculator and model pricing database for llm-cache. Computes per-request costs, tracks savings from cache hits, and ships with reference pricing for 40+ models across OpenAI, Anthropic, and Google.

Installation

terminal
npm install @reaatech/llm-cache-cost-tracker
# or
pnpm add @reaatech/llm-cache-cost-tracker

Feature Overview

  • Per-request cost calculation — input and output cost from token counts and model pricing
  • 40+ pre-configured models — OpenAI, Anthropic, and Google pricing data included
  • Savings computation — calculateSavings() returns percentage and absolute savings from cache hits
  • Extensible pricing — register custom or updated pricing via registerPricing()
  • Implements CostCalculatorLike — drop-in integration with @reaatech/llm-cache’s CostCalculatorLike interface

Quick Start

typescript
import { CostCalculator, defaultPricingDatabase } from "@reaatech/llm-cache-cost-tracker";
 
const calculator = new CostCalculator(defaultPricingDatabase);
 
const cost = calculator.calculateCost("gpt-4", 1000, 500);
// → { model: "gpt-4", inputCost: 0.03, outputCost: 0.03, totalCost: 0.06, currency: "USD" }
 
const savings = calculator.calculateSavings(0.06, 0.0001);
// → { originalCost: 0.06, cacheCost: 0.0001, totalSavings: 0.0599, savingsPercentage: 99.83 }

Integration with CacheEngine

typescript
import { CacheEngine, InMemoryAdapter, OpenAIEmbedder } from "@reaatech/llm-cache";
import { CostCalculator, defaultPricingDatabase } from "@reaatech/llm-cache-cost-tracker";
 
const cache = new CacheEngine({
  storage: new InMemoryAdapter(),
  vectorStorage: new InMemoryAdapter(),
  embedder: /* ... */,
  config: { /* ... */ },
  costCalculator: new CostCalculator(defaultPricingDatabase),
});
 
// cost tracking happens automatically on cache hits
const result = await cache.get("What is TypeScript?", {
  model: "gpt-4",
  modelVersion: "gpt-4-0613",
});

API Reference

CostCalculator (class)

typescript
import { CostCalculator } from "@reaatech/llm-cache-cost-tracker";
 
const calc = new CostCalculator();                 // empty pricing DB
const calc = new CostCalculator(customPricing);    // with initial pricing

Constructor

ParameterTypeDescription
initialPricingModelPricing[]Optional array of model pricing records to pre-register

Methods

MethodReturnsDescription
registerPricing(pricing)voidRegister or overwrite pricing for a model
calculateCost(model, promptTokens, completionTokens, currency?)CostBreakdownCompute cost from token usage
calculateSavings(originalCost, cacheCost)SavingsReportCompute savings from a cache hit

ModelPricing

typescript
interface ModelPricing {
  modelId: string;
  inputPricing: {
    per1KTokens: number;
    currency: string;
  };
  outputPricing: {
    per1KTokens: number;
    currency: string;
  };
}

CostBreakdown

Returned by calculateCost():

PropertyTypeDescription
modelstringModel identifier
promptTokensnumberInput token count
completionTokensnumberOutput token count
totalTokensnumberSum of input and output tokens
inputCostnumberCost of prompt tokens
outputCostnumberCost of completion tokens
totalCostnumberSum of input and output costs
currencystringCurrency code (default USD)

SavingsReport

Returned by calculateSavings():

PropertyTypeDescription
originalCostnumberOriginal API cost
cacheCostnumberEmbedding/retrieval cost
totalSavingsnumberoriginalCost - cacheCost
savingsPercentagenumberPercentage saved (0–100)

defaultPricingDatabase

A pre-configured ModelPricing[] array covering 40+ models from OpenAI, Anthropic, and Google. Import and pass to CostCalculator:

typescript
import { CostCalculator, defaultPricingDatabase } from "@reaatech/llm-cache-cost-tracker";
 
const calc = new CostCalculator(defaultPricingDatabase);

Usage Patterns

Custom Model Pricing

typescript
const calc = new CostCalculator();
 
calc.registerPricing({
  modelId: "my-custom-model",
  inputPricing: { per1KTokens: 0.01, currency: "USD" },
  outputPricing: { per1KTokens: 0.02, currency: "USD" },
});
 
const cost = calc.calculateCost("my-custom-model", 500, 300);

Non-USD Currency

typescript
const cost = calc.calculateCost("gpt-4", 1000, 500, "EUR");
// Returns costs in configured currency from the pricing record

Safety With Missing Models

When a model is not found in the pricing database, calculateCost() returns zero costs rather than throwing:

typescript
const cost = calc.calculateCost("unknown-model", 1000, 500);
// → { inputCost: 0, outputCost: 0, totalCost: 0, ... }

Notes

  • Pricing data is provided as reference and may lag provider price changes. Verify against your provider before relying on it for billing.
  • Token counts should be sourced from your LLM provider’s response usage field, not estimated locally.

Related Packages

License

MIT

All packagesllm-cache overview