---
title: "Update session customer"
method: PUT
path: "/v2/checkouts/{checkoutPath}/sessions/{sessionId}/customer"
tags: ["Session"]
---

# Update session customer

`PUT /v2/checkouts/{checkoutPath}/sessions/{sessionId}/customer`

Updates specific customer and billing information on an existing session. Provides a reduced scope update compared to modifying the entire session payload.

## Path parameters

- `checkoutPath` string, required — The unique identifier for the checkout instance, in the format `store-id/checkout-id` (e.g., `fastspring/main`). > **Note:** Target a specific checkout path to route the session to a single buyer experience and ensure accurate pricing. Stores frequently run multiple checkout variations simultaneously.
- `sessionId` string, required — The unique identifier of the order session.

## Request body

- CustomerRequest — Specifies the customer and billing information applied to the order session.
  - `accountId` string — The unique identifier mapping the buyer to a FastSpring account. Requires an authenticated request.
  - `externalAccountId` string, regex — An external ID used to link the buyer to your internal systems. Requires an authenticated request.
  - `billToContact` BillToContact — Capture the billing contact details used to process the payment, calculate localized taxes, and generate the invoice. Pass standard, single-buyer information here, as this acts as the primary contact for the order.
    - `email` string — The buyer's email address.
    - `firstName` string — The buyer's first name.
    - `lastName` string — The buyer's last name.
    - `company` string — The name of the buyer's company.
    - `phoneNumber` string — The buyer's phone number.
  - `billToAddress` BillToAddress — Capture the physical address associated with the buyer's payment method for tax calculation and invoicing.
    - `addressLine1` string — The first line of the address, typically the street number and name.
    - `addressLine2` string — The second line of the address, typically an apartment, suite, or unit number.
    - `city` string — The city of the address.
    - `region` string — Provide the state or province. Use the 2-letter state or province code for the USA and Canada. Use the full region name for other countries.
    - `postalCode` string — The postal or ZIP code.
  - `shipToContact` ShipToContact — Capture the recipient's contact and delivery details to ensure accurate fulfillment.
    - `email` string — The buyer's email address.
    - `firstName` string — The buyer's first name.
    - `lastName` string — The buyer's last name.
    - `company` string — The name of the buyer's company.
    - `phoneNumber` string — The buyer's phone number.
  - `shipToAddress` ShipToAddress — Capture the physical destination address to ensure accurate delivery of shipped goods.
    - `addressLine1` string — The first line of the address, typically the street number and name.
    - `addressLine2` string — The second line of the address, typically an apartment, suite, or unit number.
    - `city` string — The city of the address.
    - `region` string — Provide the state or province. Use the 2-letter state or province code for the USA and Canada. Use the full region name for other countries.
    - `postalCode` string — The postal or ZIP code.
  - `shipToType` 'GIFT_PURCHASE' | 'SHIP_TO' | 'SAME_AS_BILL_TO' — Identifies the type of shipping destination mapping applied to the order.
  - `accountTags` object — A key-value map of custom tags applied to the buyer's account. Requires an authenticated request.
  - `taxId` string — Capture the buyer's VAT, GST, or CPF identification number used for tax calculation or exemption. Required for buyers located in Brazil.
  - `taxIdRegion` string — The 2-letter state or province code associated with a US tax exemption.

## Response `200`

Successfully updated the customer details.

- CustomerResponse — Consolidates the established customer and billing data associated with the session.
  - `accountId` string — The unique identifier mapping the buyer to a FastSpring account record. Revealed only on authenticated requests.
  - `externalAccountId` string — The external ID mapping the buyer to a seller's internal platform. Revealed only on authenticated requests.
  - `savedPaymentMethod` object — The details of a previously vaulted payment method associated with the buyer's account.
    - `paymentMethodType` string — Identifies the specific payment method brand or channel.
    - `display` string — A masked identifier safely describing the vaulted payment method, generally exposing only the last 4 digits.
  - `billToContact` BillToContactResponse — The billing contact details used to process the payment, calculate localized taxes, and generate the invoice.
    - `email` string — The buyer's email address.
    - `firstName` string — The buyer's first name.
    - `lastName` string — The buyer's last name.
    - `company` string — The name of the buyer's company.
    - `phoneNumber` string — The buyer's phone number.
  - `billToAddress` BillToAddressResponse — The physical address associated with the buyer's payment method for tax calculation and invoicing.
    - `addressLine1` string — The first line of the address, typically the street number and name.
    - `addressLine2` string — The second line of the address, typically an apartment, suite, or unit number.
    - `city` string — The city of the address.
    - `region` string — Provide the state or province. Use the 2-letter state or province code for the USA and Canada. Use the full region name for other countries.
    - `postalCode` string — The postal or ZIP code.
  - `shipToContact` ShipToContactResponse — The recipient's contact and delivery details to ensure accurate fulfillment.
    - `email` string — The buyer's email address.
    - `firstName` string — The buyer's first name.
    - `lastName` string — The buyer's last name.
    - `company` string — The name of the buyer's company.
    - `phoneNumber` string — The buyer's phone number.
  - `shipToAddress` ShipToAddressResponse — The physical destination address to ensure accurate delivery of shipped goods.
    - `addressLine1` string — The first line of the address, typically the street number and name.
    - `addressLine2` string — The second line of the address, typically an apartment, suite, or unit number.
    - `city` string — The city of the address.
    - `region` string — Provide the state or province. Use the 2-letter state or province code for the USA and Canada. Use the full region name for other countries.
    - `postalCode` string — The postal or ZIP code.
  - `accountTags` object — A key-value map of custom tags applied to the buyer's account.
  - `taxId` string — The buyer's active VAT, GST, or CPF identification number.
  - `taxIdRegion` string — The 2-letter state or province code associated with a US tax exemption.

## Other responses

- `400` — Bad request. Indicates invalid input properties or values.

---

[API](https://skmtc.net/fastspring/apis/fastspring-api-accounts.md) · [All operations](https://skmtc.net/fastspring/apis/fastspring-api-accounts/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/fastspring/fastspring-api-accounts/versions/ae2f0b97db3e/schema)