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Pricing Models Demo

This example demonstrates the different pricing models supported by the library.

Running the Example​

go run ./examples/pricing-models-demo/

Supported Models​

Flat Pricing​

Simple fixed amount per billing period:

price := pricing.NewPrice(productID, moneyJPY(3000), shared.CurrencyJPY,
    pricing.BillingCycleMonthly, nil, createdAt)
// ¥3,000/month regardless of usage

Tiered Pricing​

Different rates for different usage tiers (each tier priced independently):

// NewTieredPrice validates the tiers (sorted, single currency, UpTo=0 only last)
// and returns an error on a misconfiguration.
model, err := pricing.NewTieredPrice([]pricing.PriceTier{
    {UpTo: 100, UnitPrice: moneyJPY(10), FlatFee: shared.Zero(shared.CurrencyJPY)}, // First 100: ¥10/unit
    {UpTo: 500, UnitPrice: moneyJPY(8), FlatFee: shared.Zero(shared.CurrencyJPY)},  // 101-500: ¥8/unit
    {UpTo: 0, UnitPrice: moneyJPY(5), FlatFee: shared.Zero(shared.CurrencyJPY)},    // 501+: ¥5/unit (unlimited)
}, pricing.TieredPricingGraduated)
// 250 units = (100 × ¥10) + (150 × ¥8) = ¥2,200

Volume Pricing​

Single rate based on total volume (all units priced at the tier they fall into):

// Volume pricing is the same constructor with the volume mode.
model, err := pricing.NewTieredPrice([]pricing.PriceTier{
    {UpTo: 100, UnitPrice: moneyJPY(10), FlatFee: shared.Zero(shared.CurrencyJPY)}, // 1-100 units: ¥10/unit
    {UpTo: 500, UnitPrice: moneyJPY(8), FlatFee: shared.Zero(shared.CurrencyJPY)},  // 101-500 units: ¥8/unit
    {UpTo: 0, UnitPrice: moneyJPY(5), FlatFee: shared.Zero(shared.CurrencyJPY)},    // 501+ units: ¥5/unit
}, pricing.TieredPricingVolume)
// 250 units = 250 × ¥8 = ¥2,000 (all at the ¥8 tier)

Usage-Based​

Charges based on metered usage with an included quantity:

product := product.NewProduct("API Service",
    product.WithUsageMetrics([]product.UsageMetric{
        {Name: "api_calls", IncludedQuantity: 1000},
    }),
)
price := pricing.NewPrice(product.ID(), moneyJPY(5000), shared.CurrencyJPY,
    pricing.BillingCycleMonthly, pricingModel, createdAt)
// ¥5,000 base + usage charges for API calls beyond 1,000

Key Takeaways​

  • Pricing model is defined on the Price entity, not the contract
  • Multiple prices can exist for the same product (monthly/yearly, different tiers)
  • Per-contract price overrides allow custom negotiated pricing
  • Usage metrics are defined on the Product, pricing rules on the Price