---
updatedAt: 2025-09-08T21:43:43.000Z
agentTools:
  projectIndex: https://docs.asaas.com/llms.txt
---

# How to provide customer data

When creating a checkout, you have three ways to provide customer information:

**Using the`customerData` field (manual data)**\
Ideal when you haven’t registered the customer in Asaas yet or want to pre-fill the checkout automatically.

You provide the data directly in the request body.

Example:

```json
"customerData": {  
  "name": "Ana Paula",  
  "cpfCnpj": "12345678900",  
  "email": "ana@email.com",  
  "phone": "47988887777",  
  "address": "Rua das Flores",  
  "addressNumber": 123,  
  "complement": "Casa",  
  "postalCode": "89000000",  
  "province": "Centro",  
  "city": 4205407  
}
```

This information will already be filled in on the checkout page, making payment easier and reducing friction for the customer.

**Using the`customer` field (ID of an existing customer)**\
Ideal when the customer has already been registered via the API or the Asaas dashboard.

You only need to provide the customer ID (e.g., `cus_000005821234`), and Asaas will automatically retrieve the stored information.

Example:

```json
"customer": "cus_000005821234"
```

The checkout will be generated with the customer’s data pre-filled, such as name, email, CPF, address, etc., as stored in the record.

> 🚧 **Important**
>
> * You must use only one of the two fields: `customerData` or `customer`.
> * Providing both at the same time is not allowed.
> * If using `customer`, make sure the customer already exists in the Asaas database.

**Letting your customer enter the data**

If you don’t send either of the above fields, your customer will be able to enter their own information directly on the checkout page.

# Sibling pages

* [Introduction - Asaas Checkout](https://docs.asaas.com/docs/introduction-1.md)
* [Checkout for Pix](https://docs.asaas.com/docs/checkout-for-pix.md)
* [Checkout for Credit Card](https://docs.asaas.com/docs/checkout-for-credit-card.md)
* [Checkout with Subscription (Recurring)](https://docs.asaas.com/docs/checkout-with-subscription-recurring.md)
* [Checkout with Payment Split](https://docs.asaas.com/docs/checkout-with-payment-split.md)
* [Checkout link and customer redirection](https://docs.asaas.com/docs/checkout-link-and-customer-redirection.md)
* [Common errors and best practices](https://docs.asaas.com/docs/common-errors-and-best-practices.md)