> ## Documentation Index > Fetch the complete documentation index at: https://docs.y.uno/llms.txt > Use this file to discover all available pages before exploring further. # Update Checkout Session Update an existing checkout session with this endpoint. Only fields you send will be updated. ## OpenAPI ````yaml openapi/checkout-sessions/update-checkout-session.json PATCH /checkout/sessions/{checkout_session} openapi: 3.1.0 info: title: checkout-api version: 1.0.2 servers: - url: https://api-sandbox.y.uno/v1 security: - sec0: [] sec1: [] paths: /checkout/sessions/{checkout_session}: patch: summary: Copy of Create Checkout Session operationId: post_checkoutsessions-1 parameters: - in: path name: checkout_session schema: type: string required: true requestBody: content: application/json: schema: type: object required: - merchant_order_id - payment_description - country - account_id properties: customer_id: type: string description: >- The unique identifier of the customer, created using the [Create Customer](https://docs.y.uno/reference/create-customer) endpoint (UUID, 36 chars). merchant_order_id: type: string description: >- The unique identifier of the customer's order (MAX 255; MIN 3). payment_description: type: string description: The description of the payment (MAX 255; MIN 3). callback_url: type: string description: >- The URL where we will redirect your customer after making the purchase. Required for alternative payment methods with redirection. (MAX 526; MIN 3) country: type: string description: >- The customer's country (MAX 2; MIN 2; [ISO 3166-1](country-reference)). enum: - AR - BO - BR - CL - CO - CR - EC - SV - GT - HN - MX - NI - PA - PY - PE - US - UY account_id: type: string description: >- The unique identifier of the account. You find this information on [the Yuno dashboard](https://dashboard.y.uno/) (UUID, 36 chars). default: '{{account_id}}' amount: type: object description: >- Specifies the payment amount object, with the value and currency. required: - currency - value properties: currency: type: string description: >- The currency used to make the payment. For a full list of currency codes, see [Country reference](/reference/country-reference) (MAX 3; MIN 3; ISO 4217). value: type: number description: The payment amount (multiple of 0.0001). format: float alternative_amount: type: object description: >- Alternative currency representation of the transaction amount. required: - currency - value properties: currency: type: string description: >- The alternative currency code. For a full list of currency codes, see [Country reference](/reference/country-reference) (MAX 3; MIN 3; ISO 4217). nullable: true value: type: number description: The alternative amount value (multiple of 0.0001). format: float metadata: type: array description: >- Specifies a list of metadata objects. You can add up to 120 metadata objects. items: properties: key: type: string description: The metadata key (MAX 48) value: type: string description: The metadata key value (MAX 512) required: - key - value type: object workflow: type: string description: Checkout workflow type. enum: - SDK_CHECKOUT - CHECKOUT - SDK_SEAMLESS installments: type: object description: >- The object to send the installment plan created in Yuno to show your customers and let them choose from. This optional field is used in case a particular installments plan needs to be used in the session. if not sent, we will display the installment plan created for the account for each scenario, if any. properties: plan_id: type: string description: Plan Id of the installment plan created in Yuno plan: type: array description: >- Installments to show the customer in with the checkout_session. This optional struct is used in case a particular installments plan needs to be used in the session and does not have an installments plan created for it. if not sent, we will display the installment plan created for the account for each scenario, if any. items: properties: installment: type: integer description: >- The number of monthly installments shoppers can choose format: int32 rate: type: number description: >- The rate applied to the final amount of the transaction by the payment provider after using installments. The value should be entered as a multiplier, not a percentage. For example, to apply a 20% rate, enter `1.20` instead of `20`. format: float required: - installment - rate type: object examples: Update checkout session: value: country: BR amount: currency: ARS alternative_amount: currency: ARS merchant_order_id: '007' payment_description: Payment Test account_id: '{{account_id}}' summary: Update checkout session responses: '200': description: '200' content: application/json: examples: Success: value: merchant_order_id: '007' checkout_session: c67ce158-6053-4661-a1de-aed5c945b935 country: BR payment_description: Payment Test callback_url: null amount: currency: ARS value: 100 created_at: '2025-11-14T00:43:22.719648Z' metadata: null workflow: SDK_CHECKOUT installments: plan_id: null plan: null used: false summary: Success schema: type: object properties: merchant_order_id: type: string example: '007' checkout_session: type: string example: c67ce158-6053-4661-a1de-aed5c945b935 country: type: string example: BR payment_description: type: string example: Payment Test callback_url: {} amount: type: object properties: currency: type: string example: ARS value: type: integer example: 100 default: 0 created_at: type: string example: '2025-11-14T00:43:22.719648Z' metadata: {} workflow: type: string example: SDK_CHECKOUT installments: type: object properties: plan_id: {} plan: {} used: type: boolean example: false default: true '400': description: '400' content: application/json: examples: Bad Request: value: code: INVALID_REQUEST messages: - Invalid request schema: type: object properties: code: type: string example: INVALID_REQUEST messages: type: array items: type: string example: Invalid request '401': description: '401' content: application/json: examples: Unauthorized: value: code: INVALID_CREDENTIALS messages: - Invalid credentials schema: type: object properties: code: type: string example: INVALID_CREDENTIALS messages: type: array items: type: string example: Invalid credentials '403': description: '403' content: application/json: examples: Forbidden: value: code: AUTHORIZATION_REQUIRED messages: - The merchant has no authorization to use this API. schema: type: object properties: code: type: string example: AUTHORIZATION_REQUIRED messages: type: array items: type: string example: The merchant has no authorization to use this API. deprecated: false components: securitySchemes: sec0: type: apiKey in: header name: public-api-key x-default: sec1: type: apiKey in: header name: private-secret-key x-default: ````