> ## Documentation Index
> Fetch the complete documentation index at: https://yn-c9bb3266.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# The Customer Session Object

> Represents a customer session used to manage payment method enrollment and one-click checkout.

The Customer Session object generates an `sdk_token` scoped to a specific customer, enabling client-side operations like payment method enrollment (vaulting), listing saved methods, and one-click checkout. Unlike a Checkout Session, a Customer Session does not involve a payment amount. It is purely for credential management.

<Info>
  **Enrollment flow**. To vault a payment method for future use, create a Customer Session first, then use the returned `sdk_token` to initialize the enrollment SDK on the client side. See [Enrollment Guide](/guides/enrollment).
</Info>

## Object Fields

<ResponseField name="id" type="string">
  The unique identifier for this customer session (UUID).

  Example: `cs_7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d`
</ResponseField>

<ResponseField name="customer_id" type="string">
  The ID of the [Customer Object](/api-reference/customers/object) this session belongs to. The customer must exist before creating a session.

  Example: `c9d0e1f2-3a4b-5c6d-7e8f-9a0b1c2d3e4f`
</ResponseField>

<ResponseField name="status" type="string">
  Current status of the customer session.

  Values: `ACTIVE`, `EXPIRED`

  Example: `ACTIVE`
</ResponseField>

<ResponseField name="sdk_token" type="string">
  Token used to initialize the Yuno SDK for enrollment flows on the client side. Returned only in the create response. Scoped to the customer and short-lived.

  Example: `cstok_live_xyz789abc012def345ghi678`
</ResponseField>

<ResponseField name="expires_at" type="string">
  ISO 8601 timestamp of when this session expires. After expiration, the `sdk_token` is no longer valid and a new session must be created.

  Example: `2026-03-10T19:00:00.000Z`
</ResponseField>

<ResponseField name="created_at" type="string">
  ISO 8601 timestamp of when the customer session was created.

  Example: `2026-03-10T18:00:00.000Z`
</ResponseField>

## Example

```json theme={"theme":{"light":"github-dark","dark":"github-dark"}}
{
  "id": "cs_7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d",
  "customer_id": "c9d0e1f2-3a4b-5c6d-7e8f-9a0b1c2d3e4f",
  "status": "ACTIVE",
  "sdk_token": "cstok_live_xyz789abc012def345ghi678",
  "expires_at": "2026-03-10T19:00:00.000Z",
  "created_at": "2026-03-10T18:00:00.000Z"
}
```

## Session Lifecycle

Customer sessions follow a simple lifecycle:

| Status    | Description                                                                     |
| --------- | ------------------------------------------------------------------------------- |
| `ACTIVE`  | Session is valid. The `sdk_token` can be used to initialize the enrollment SDK. |
| `EXPIRED` | Session has passed its `expires_at` time. Create a new session to continue.     |

<Warning>
  Customer sessions are short-lived by design. Always create a fresh session immediately before rendering the enrollment UI. Do not cache or reuse `sdk_token` values across page loads.
</Warning>

## Checkout Session vs. Customer Session

These two session types serve different purposes:

|                       | Checkout Session                 | Customer Session                   |
| --------------------- | -------------------------------- | ---------------------------------- |
| **Purpose**           | Collect a payment                | Enroll a payment method            |
| **Requires amount**   | Yes                              | No                                 |
| **Creates a payment** | Yes                              | No                                 |
| **Vaults a method**   | Only if `vault_on_success: true` | Always (that is the purpose)       |
| **SDK flow**          | Checkout SDK                     | Enrollment SDK                     |
| **Endpoint**          | `POST /v1/checkout/sessions`     | `POST /v1/customers/{id}/sessions` |

## Common Integration Pattern

A typical enrollment flow using Customer Sessions:

1. **Create the customer** via `POST /v1/customers` if they do not already exist.
2. **Create a Customer Session** via `POST /v1/customers/{customer_id}/sessions`.
3. **Initialize the SDK** on the client side using the returned `sdk_token`.
4. **Customer completes enrollment**. The SDK handles the card form, tokenization, and verification.
5. **Receive webhook** confirming the payment method was enrolled.
6. **Use the vaulted token** in future [Checkout Sessions](/api-reference/checkout-sessions/create) for one-click payments.

<Info>
  **Sandbox testing**. In sandbox, use Yuno's test card numbers to simulate enrollment. The session behaves identically to production, but no real card verification occurs.
</Info>

## Related Endpoints

* [Create Customer Session](/api-reference/customer-sessions/create). `POST /v1/customers/{customer_id}/sessions`

## Related Concepts

* [Enrollment Guide](/guides/enrollment). Step-by-step guide to vaulting payment methods
* [Customer Object](/api-reference/customers/object). The customer record this session is scoped to
* [Payment Method Object](/api-reference/payment-methods/object). Payment methods enrolled through this session
* [Checkout Session Object](/api-reference/checkout-sessions/object). The session type used for collecting payments
* [One-Click Checkout](/guides/one-click). Using vaulted methods for returning customers