***
title: 'Overview: Product catalog'
subtitle: >-
The product catalog is the foundation of your billing system. Define products,
set up pricing models, and configure how customers are charged.
---------------------------------------------------------------
# Core concepts
PaymentKit's product catalog is built on **two main entities:**
| Entity | Description |
| ------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------- |
| [**Products**](https://docs.paymentkit.com/guides/product-catalog/overview#products) | The items or services you sell, each with a name, description, and unit label. |
| [**Prices**](https://docs.paymentkit.com/guides/product-catalog/overview#prices) | How and when you charge for a product, including amount, currency, and billing behavior. |
***
# Products
A product represents something you sell. Each product can have multiple prices for different billing models, currencies, or tiers.
**Key product fields:**
| Field | Description |
| --------------- | ------------------------------------------------------------------------------------------------ |
| **Name** | Display name shown to customers |
| **Description** | Optional details about the product that will appear in checkout/customer billing portal sessions |
***
# Prices
Prices define how much to charge for a product. A single product can have multiple prices for different scenarios.
**Key price fields:**
| Field | Description |
| --------------------- | --------------------------------------------------- |
| **Pricing model** | When customers are charged (flat or usage-based) |
| **Pricing structure** | How the price scales (fixed, tiered, or package) |
| **Amount** | The price in minor units (cents for USD) |
| **Currency** | ISO 4217 currency code (e.g., "usd", "eur") |
| **Billing period** | How often recurring charges occur (monthly, yearly) |
## Pricing models
A pricing model defines how and when customers are charged for a product. PaymentKit supports the following pricing models:
Charge a fixed amount regardless of quantity or usage—works for both one-time and recurring billing (e.g., \$29/month).
Metered, measured, billed after usage—charge is based on *actual consumption over time* (e.g., \$0.01 per API call).
## Pricing structures
A pricing structure defines how the unit price changes as quantity or usage increases. PaymentKit supports the following pricing structures:
Charge a fixed price for each unit of a product or service, regardless of quantity.
Charge different prices based on quantity thresholds using graduated or volume tiers.
Charge a fixed price for a predefined bundle of units, rather than pricing each unit individually.
***
## Example: SaaS product catalog
A typical SaaS product catalog might look like:
```
Products:
├── Pro Plan (flat)
│ ├── Price: $29/month
│ └── Price: $290/year
├── Enterprise Plan (flat)
│ ├── Price: $99/month
│ └── Price: $990/year
├── Additional Seats (flat, fixed structure)
│ └── Price: $10/seat/month
└── Storage Add-on (usage-based, tiered structure)
└── Price: $0.10/GB/month
```
***
# Packages, discounts, and upgrade paths
Present multiple related products together at checkout and let customers select the option that fits their needs.
Apply discounts to products or prices using configurable percentage or fixed-amount rules.
Control how customers can move between products by defining allowed upgrade and downgrade paths.