> ## Documentation Index
> Fetch the complete documentation index at: https://docs.valyx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Usage Driver

A **Usage Driver** defines how usage is measured in the system.  It determines the quantity based on which a **Fee Component** is billed. For example -

<Tabs>
  <Tab title="Cloud SaaS">
    Let's say you're offering a cloud storage service.

    * **Fee Component**: `Storage Charges`  This is the invoice line item representing the cost of storing data.
    * **Usage Driver**: `Storage Used` This tracks how much storage space a customer consumes — typically measured in gigabytes (GB) per month.

    While the system internally measures usage using the usage driver `(Storage Used)`, this raw metric isn’t shown directly on the invoice. Instead, the invoice displays the fee component `(Storage Charges)` along with the billed amount. The usage driver to fee component mapping allows you to:

    * Track usage in technical units (e.g. GB, API calls)
    * Translate it into meaningful, customer-facing charges

    > This separation makes your billing more flexible, allowing you to change how you measure usage without changing how it’s presented to your customer.
  </Tab>

  <Tab title="Logistics">
    Let's say you're running a logistics company.

    * **Fee Component**: `Courier Fees`  This is the line item shown on the invoice, representing the delivery charges billed to the customer.
    * **Usage Driver**: `Parcel Weight`    This tracks the weight of each parcel being shipped, typically measured in kilograms (kg).

    Although the system measures usage using the **Usage Driver** (`Parcel Weight`), this technical detail isn’t shown on the customer invoice.  What the customer sees is the **Fee Component** (`Courier Fees`) and the amount charged.

    The **Usage Driver to Fee Component mapping** enables you to:

    * Track operational metrics (e.g. weight, distance, volume)
    * Convert them into clear, business-facing charges on the invoice
  </Tab>
</Tabs>

### Usage Driver To Fee Component Mapping

One usage driver can be associated with multiple fee components (and vice-versa). For example - If you are sending a parcel with a particular weight, you might want to add both logistic fees and tracking fees basis that.\
\
While generally, usage driver and fee component quantities are same, Valyx allows you to define custom multipliers (any decimal value) as well.  For ex - 1 unit of weight might imply 100 units of logistics fees incurred.