> For the complete documentation index, see [llms.txt](https://plexo.gitbook.io/rest-api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://plexo.gitbook.io/rest-api/core-concepts/customers.md).

# Customers

*Brief explanation: A customer represents the person or entity making a payment. Customers can have associated payment instruments (tokenized cards) for recurring payments. `FirstName`, `LastName`, and `Email` are optional on create and update; a supplied `Email` must be syntactically valid. `ReferenceId` is required when creating a customer.*

## What is a Customer?

A customer in Plexo represents a buyer or payer who makes purchases through your merchant account. Customers are optional but recommended for:

* Recurring payments and subscriptions
* Storing tokenized payment methods
* Tracking customer payment history
* Pre-filling payment information

## Customer Properties

**Key Fields:**

* `Id` - Unique Plexo identifier (UUID)
* `ReferenceId` - Your system's customer identifier (required on create)
* `Email` - Optional customer email address (syntactically valid when supplied)
* `FirstName` / `LastName` - Optional customer name
* `Phone` - Contact phone number
* `Document` / `Identification` - Identity document (CI, RUT, CPF, etc.)
* `Address` - Billing address
* `Birthdate` - Date of birth
* `Metadata` - Custom key-value data
* `Status` - Customer status

## Payment Instruments

Customers can have multiple tokenized payment instruments (cards) associated with their account. These tokens can be used for:

* One-click checkout
* Recurring billing
* Subscription payments
* Card-on-file transactions

## Customer Lifecycle

1. **Create Customer**: Register a new customer with contact information
2. **Add Payment Instruments**: Tokenize and store payment methods
3. **Process Payments**: Use stored instruments for transactions
4. **Update Information**: Modify customer details as needed
5. **Delete Customer**: Remove customer and associated data

## Use Cases

**When to Use Customers:**

1. **Recurring Payments** - Store payment methods for subscription billing
2. **Improved UX** - Pre-fill checkout forms with saved information
3. **Customer Analytics** - Track payment behavior and history
4. **Compliance** - Store customer data for regulatory requirements

**When Customers are Optional:**

* One-time guest checkouts
* Simple payment flows
* Anonymous transactions

## Related Resources

* [Customer Management Guide](/rest-api/customers-and-saved-methods/customer-management.md)
* [Tokenization](/rest-api/core-concepts/tokenization.md)
* [Recurring Payments](/rest-api/customers-and-saved-methods/recurring-payments.md)