> ## Documentation Index > Fetch the complete documentation index at: https://docs.fynn.eu/llms.txt > Use this file to discover all available pages before exploring further. # Changes the quantity of a cart item. > Changes the quantity of a cart item. ## OpenAPI ````yaml put /public/checkout/cart/{id}/change-quantity openapi: 3.1.0 info: title: Fynn API description: '' termsOfService: https://www.fynn.eu/tos contact: name: Fynn UG (haftungsbeschränkt) url: https://www.fynn.eu email: hi@fynn.eu license: name: Proprietary url: https://www.fynn.eu/license version: 0.0.0 servers: - url: https://coreapi.io description: Production - url: https://preview.coreapi.io description: Sandbox security: - JWT: [] tags: [] paths: /public/checkout/cart/{id}/change-quantity: parameters: [] put: tags: - Cart summary: Changes the quantity of a cart item. description: Changes the quantity of a cart item. operationId: api_publiccheckoutcart_idchange-quantity_put parameters: - name: id in: path description: Cart identifier required: true deprecated: false schema: type: string style: simple explode: false requestBody: description: The updated Cart resource content: application/json: schema: $ref: '#/components/schemas/Cart.ChangeCartItemQuantity' text/html: schema: $ref: '#/components/schemas/Cart.ChangeCartItemQuantity' required: true responses: '200': description: Cart resource updated content: application/json: schema: $ref: '#/components/schemas/Cart.CartResource-CartPublic' text/html: schema: $ref: '#/components/schemas/Cart.CartResource-CartPublic' links: {} '400': description: Invalid input '404': description: Resource not found '422': description: Unprocessable entity deprecated: false x-codeSamples: - lang: bash label: cURL source: |- curl -X PUT \ /public/checkout/cart/{id}/change-quantity \ --header "Content-Type: application/json" \ --header "Authorization: Bearer " \ --data '{ "cartItemId": "" }' components: schemas: Cart.ChangeCartItemQuantity: type: object description: '' deprecated: false required: - quantity properties: quantity: description: The new quantity of the cart item. example: 10 cartItemId: type: string Cart.CartResource-CartPublic: type: object description: '' deprecated: false properties: price: $ref: '#/components/schemas/CartPriceResource-CartPublic' id: example: c1b0d0c0-0b0b-4b0b-8b0b-0b0b0b0b0b0b type: string status: description: |- The status of the cart. Possible values: * `open`: The cart is open and can be edited. * `confirming`: The cart is confirming and cannot be edited. example: open customer: description: The customer who owns the cart. example: c1b0d0c0-0b0b-4b0b-8b0b-0b0b0b0b0b0b type: - string - 'null' email: type: - string - 'null' invoiceAddress: anyOf: - $ref: '#/components/schemas/CustomerAddress-CartPublic' - type: 'null' customerPrefill: description: >- The customer prefill data which should be used to prefill the checkout form. anyOf: - $ref: '#/components/schemas/CustomerPrefill-CartPublic' - type: 'null' paymentMethod: description: The payment method which should be used for the cart. example: c1b0d0c0-0b0b-4b0b-8b0b-0b0b0b0b0b0b anyOf: - $ref: '#/components/schemas/PaymentMethod-CartPublic' - type: 'null' items: description: The items of the cart. type: array items: $ref: '#/components/schemas/CartItemResource-CartPublic' completionDetails: description: Details shown to the customer when the cart is completed. type: - array - 'null' items: type: string settings: $ref: '#/components/schemas/CartSettingsResource-CartPublic' description: The settings of the cart. CartPriceResource-CartPublic: type: object description: '' deprecated: false properties: amountDue: type: number currencyCode: $ref: '#/components/schemas/CurrencyCode-CartPublic' netAmount: type: number taxes: type: array items: $ref: '#/components/schemas/CartPriceTaxResource-CartPublic' discountDetails: type: - array - 'null' items: type: string CustomerAddress-CartPublic: type: object description: '' deprecated: false properties: id: readOnly: true type: string vatId: description: >- VAT ID, which will be used to bill to. If not provided, we will use the customer vat id. example: DE123456789 type: - string - 'null' type: example: TYPE_DEFAULT enum: - TYPE_DEFAULT - TYPE_INVOICE default: example: 'true' type: boolean status: readOnly: true example: active enum: - active - archived city: example: Berlin type: string zip: example: '12345' type: string street: example: Musterstraße type: string houseNumber: example: 1a type: string countryCode: example: DE type: string companyName: description: Company name, which will be used to bill to. example: ACME Inc. type: - string - 'null' salutation: example: Herr enum: - Firma - Herr - Frau addition: description: >- Additional address information, which will be shown on generated documents like invoices, reminders, etc. example: c/o John Doe type: - string - 'null' costCentre: description: >- Cost centre, which will be shown on generated documents like invoices, reminders, etc. example: '123456789' type: - string - 'null' firstName: description: >- First name, which will be shown on generated documents like invoices, reminders, etc. example: John type: - string - 'null' lastName: description: >- Last name, which will be shown on generated documents like invoices, reminders, etc. example: Doe type: - string - 'null' CustomerPrefill-CartPublic: type: object description: '' deprecated: false PaymentMethod-CartPublic: type: object description: '' deprecated: false properties: id: readOnly: true type: string description: Unique identifier of the payment method example: c1a2b3c4-d5e6-4f7a-8b9b-0c1d2e3f4a5b gatewayName: type: string enum: - wallet - sepa_debit - stripe - fake_provider - paypal - bank_transfer - go_cardless - testing description: The payment gateway used to process the payment method type: type: - string - 'null' enum: - sepa_debit - card - paypal - bank_transfer - wallet - fake_provider - null description: The type of the payment method default: type: boolean description: Whether this is the default payment method for the customer example: true status: default: active example: active type: string enum: - active - action_required - expired - revoked - gateway_unconfigured description: The current status of the payment method enabled: type: boolean description: Whether the payment method is enabled for use example: true name: type: - string - 'null' description: Display name of the payment method example: Visa (4242) creationDate: readOnly: true type: string format: date-time description: The date when the payment method was created example: '2024-01-15T10:30:00+00:00' expirationDate: type: - string - 'null' format: date-time description: The expiration date of the payment method, if applicable example: '2026-12-31T23:59:59+00:00' card: readOnly: true description: The card data of the payment method, if the type is "card" type: object properties: brand: type: string example: Visa description: The brand of the card last4: type: string example: '4242' description: The last 4 digits of the card expMonth: type: integer example: 12 description: The expiration month of the card expYear: type: integer example: 2022 description: The expiration year of the card cardHolder: type: string example: Max Mustermann description: The card holder name sepaDebit: readOnly: true description: >- The sepa mandate data of the payment method, if the type is "sepa_debit" type: object properties: iban: type: string example: DE8937*********3232 description: The iban of the sepa mandate bic: type: string example: COBADEFFXXX description: The bic of the sepa mandate mandateReference: type: string example: MNDT-2021-123456 description: The mandate reference of the sepa mandate signingDate: type: string example: '2021-01-01T00:00:00+00:00' description: The signing date of the sepa mandate paypal: readOnly: true description: The paypal data of the payment method, if the type is "paypal" type: object properties: email: type: string example: max@mustermann.de description: The email of the paypal account billingAgreementId: type: string example: I-1J5gqz2eZvKYlo2C2X2X2X2X description: The billing agreement id of the paypal account CartItemResource-CartPublic: type: object description: '' deprecated: false properties: id: type: string name: type: string description: type: - string - 'null' quantity: $ref: '#/components/schemas/Quantity-CartPublic' quantityDetails: $ref: '#/components/schemas/CartItemQuantityResource-CartPublic' price: $ref: '#/components/schemas/CartItemPriceResource-CartPublic' type: type: string enum: - product periods: type: array items: $ref: '#/components/schemas/CartItemTermResource-CartPublic' CartSettingsResource-CartPublic: type: object description: '' deprecated: false properties: allowCoupons: description: Whether coupons can be applied to the checkout link or not. type: boolean forceCompany: description: Whether the company should be forced in the checkout form or not. type: boolean backButton: description: The URL to redirect to when the back button is clicked. example: url: https://example.com label: Back to the shop type: - array - 'null' items: type: string CurrencyCode-CartPublic: type: string description: ISO 4217 currency code. example: EUR CartPriceTaxResource-CartPublic: type: object description: '' deprecated: false properties: netAmount: type: number taxAmount: type: number rate: type: integer Quantity-CartPublic: type: - number - 'null' description: A numeric quantity value. example: 1 CartItemQuantityResource-CartPublic: type: object description: '' deprecated: false properties: aggregationType: type: string enum: - count - count_unique - max - sum - average - last_value unit: type: string description: type: - string - 'null' quantityEditable: type: boolean CartItemPriceResource-CartPublic: type: object description: '' deprecated: false properties: currencyCode: $ref: '#/components/schemas/CurrencyCode-CartPublic' taxRate: description: If null, the customer has not yet provided a invoice address. type: - integer - 'null' totalNetAmount: description: The total net amount for this cart item which is now due. example: 10 type: number type: type: string enum: - recurring - metered - instant_metered calculationType: type: string enum: - flat_fee - per_unit - tiered - volume - stair_step - percentage payInAdvance: type: boolean price: anyOf: - $ref: '#/components/schemas/FlatFeePrice-CartPublic' - $ref: '#/components/schemas/PercentagePrice-CartPublic' - $ref: '#/components/schemas/PerUnitPrice-CartPublic' - $ref: '#/components/schemas/TieredPrice-CartPublic' recurring: anyOf: - $ref: '#/components/schemas/CartItemRecurringResource-CartPublic' - type: 'null' freeUnits: anyOf: - $ref: '#/components/schemas/Quantity-CartPublic' - type: 'null' CartItemTermResource-CartPublic: type: object description: '' deprecated: false properties: contractPeriod: type: string cancellationPeriod: type: string FlatFeePrice-CartPublic: type: object description: '' deprecated: false required: - amount properties: amount: description: The amount of the flat fee per unit type: number PercentagePrice-CartPublic: type: object description: '' deprecated: false required: - percentage - fixedAmount - freeUnitsPerEvent - freeUnitsPerBillingInterval properties: percentage: description: The percentage of the total amount that is charged. type: number fixedAmount: description: >- The fixed amount that is charged per unit, metered in the billing period. E.g. on pushing 1000 units, the fixed amount is charged 1000 times * percentage type: number freeUnitsPerEvent: description: The number of units that are not subject to the fixed fee. type: integer freeUnitsPerBillingInterval: description: The amount that is not subject to the charge rate. type: number PerUnitPrice-CartPublic: type: object description: '' deprecated: false required: - amount properties: amount: description: The amount of money per unit example: 0.99 type: number TieredPrice-CartPublic: type: object description: '' deprecated: false required: - items properties: items: minItems: 1 type: array items: $ref: '#/components/schemas/TierItem-CartPublic' CartItemRecurringResource-CartPublic: type: object description: '' deprecated: false properties: interval: type: string enum: - day - week - month - year intervalCount: type: integer trialPeriodDays: type: - integer - 'null' recurringAmount: type: number TierItem-CartPublic: type: object description: '' deprecated: false properties: id: readOnly: true type: string from: description: The lower bound of the tier type: number amount: description: The amount of the tier per unit type: number flatAmount: description: >- The flat amount of the tier, billed once in addition to the amount per unit in a billing period type: number required: - from - amount - flatAmount securitySchemes: JWT: type: http scheme: bearer ````