> For the complete documentation index, see [llms.txt](https://apidocs.akinon.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://apidocs.akinon.com/commerce-openapis/checkout/promotions-and-extras/add-or-remove-a-coupon.md).

# Add or Remove a Coupon

Adds or removes a coupon from the current checkout session. This is an independent step and does not determine the next checkout page. The checkout flow proceeds based on the current checkout state.

**Required Fields**:

* `coupon`: The primary key of the `BasketOffer` record as a string
* `action`: Either `"add"` to apply the coupon or `"remove"` to unapply it

**State Changes**:

* The coupon PK is added to or removed from `pre_order.data["coupons"]`
* Offer applications are recalculated on the next GET request

```json
{"openapi":"3.1.0","info":{"title":"Overview","version":"1.0.0"},"tags":[{"name":"Promotions & Extras","description":"# Checkout Promotions & Extras\n\nApply discounts and promotional offers that reduce the order total or add complimentary items.\n\n**Coupons** apply a single-use discount code to the basket.\n\n**Vouchers** apply a voucher code that may provide a fixed or percentage discount.\n\n**Campaigns** present available promotional campaigns the customer can activate.\n\n**Sample Products** let customers add a complimentary product sample to their order.\n\n## Authentication\n\nThese endpoints support both authenticated and anonymous sessions.\n\n- **Authenticated users**: Session cookie (`sessionid`) tracks checkout progress.\n- **Anonymous users**: Guest checkout is available when the `CAN_GUEST_PURCHASE` setting is enabled.\n## Request Format\n\nInclude the following header in all checkout requests:\n\n- **x-requested-with**: `XMLHttpRequest`"}],"servers":[{"description":"Akinon Checkout API","url":"https://{commerce_url}","variables":{"commerce_url":{"default":"sandbox.akinon.com"}}}],"paths":{"/orders/checkout/?page=CouponSelectionPage":{"post":{"tags":["Promotions & Extras"],"operationId":"submitCouponSelection","summary":"Add or Remove a Coupon","description":"Adds or removes a coupon from the current checkout session.\nThis is an independent step and does not determine the next checkout page.\nThe checkout flow proceeds based on the current checkout state.\n\n**Required Fields**:\n- `coupon`: The primary key of the `BasketOffer` record as a string\n- `action`: Either `\"add\"` to apply the coupon or `\"remove\"` to unapply it\n\n**State Changes**:\n- The coupon PK is added to or removed from `pre_order.data[\"coupons\"]`\n- Offer applications are recalculated on the next GET request","parameters":[{"$ref":"#/components/parameters/AjaxRequestHeader"},{"$ref":"#/components/parameters/SessionCookieHeader"}],"requestBody":{"required":true,"content":{"application/x-www-form-urlencoded":{"schema":{"$ref":"#/components/schemas/CouponSelectionInput"}}}},"responses":{"200":{"description":"Coupon action processed","content":{"application/json":{"schema":{"$ref":"#/components/schemas/CheckoutResponse"}}}}}}}},"components":{"parameters":{"AjaxRequestHeader":{"name":"x-requested-with","in":"header","required":true,"description":"Required header for AJAX requests. Must be set to `XMLHttpRequest` for all checkout requests.","schema":{"type":"string","enum":["XMLHttpRequest"],"default":"XMLHttpRequest"}},"SessionCookieHeader":{"name":"Cookie","in":"header","required":false,"description":"Session cookie header (e.g. `sessionid=abc123` or `osessionid=<session_id>`)","schema":{"type":"string"}}},"schemas":{"CouponSelectionInput":{"type":"object","required":["coupon","action"],"properties":{"coupon":{"type":"string","description":"Primary key of the `BasketOffer` record to add or remove, as a string."},"action":{"type":"string","description":"Action to perform: `\"add\"` to apply the coupon or `\"remove\"` to unapply it.","enum":["add","remove"]}}},"CheckoutResponse":{"type":"object","properties":{"context_list":{"type":"array","items":{"$ref":"#/components/schemas/PageContext"}},"pre_order":{"$ref":"#/components/schemas/PreOrder"},"errors":{"oneOf":[{"type":"object","additionalProperties":{"type":"array","items":{"type":"string"}}},{"type":"null"},{"type":"array","items":{"type":"string"}}]},"template_name":{"type":"string"}}},"PageContext":{"type":"object","properties":{"page_name":{"type":"string","description":"Class name of the page (e.g., \"IndexPage\", \"AddressSelectionPage\")"},"page_slug":{"type":"string","description":"URL-friendly slug for the page"},"page_context":{"type":"object","description":"Page-specific context data","additionalProperties":true}}},"PreOrder":{"type":"object","description":"Pre-order state containing basket, addresses, shipping, payment information","properties":{"basket":{"$ref":"#/components/schemas/Basket"},"shipping_address":{"oneOf":[{"$ref":"#/components/schemas/Address"},{"type":"null"}]},"billing_address":{"oneOf":[{"$ref":"#/components/schemas/Address"},{"type":"null"}]},"shipping_option":{"oneOf":[{"$ref":"#/components/schemas/ShippingOptionDetail"},{"type":"null"}]},"billing_and_shipping_same":{"oneOf":[{"type":"boolean"},{"type":"null"}]},"payment_option":{"oneOf":[{"$ref":"#/components/schemas/PaymentOptionDetail"},{"type":"null"}]},"notifications":{"type":"array","items":{"type":"object"}},"shipping_amount":{"oneOf":[{"type":"string","pattern":"^\\d+\\.\\d{2}$"},{"type":"null"}]},"total_amount":{"oneOf":[{"type":"string","pattern":"^\\d+\\.\\d{2}$"},{"type":"null"}]},"unpaid_amount":{"oneOf":[{"type":"string","pattern":"^\\d+\\.\\d{2}$"},{"type":"null"}]},"loyalty_money":{"oneOf":[{"type":"string","pattern":"^\\d+\\.\\d{2}$"},{"type":"null"}]},"currency_type_label":{"type":"string"},"installment":{"oneOf":[{"$ref":"#/components/schemas/Installment"},{"type":"null"}]},"card_info":{"oneOf":[{"type":"object","description":"Card information from BIN lookup","properties":{"bin_number":{"type":"string","description":"Card BIN (first 6-8 digits)"},"card":{"type":"object","description":"Card details from BIN database","properties":{"pk":{"type":"integer"},"name":{"type":"string","description":"Card type name (e.g., \"Visa\", \"Mastercard\")"}}}}},{"type":"null"}]},"redirect_to_three_d":{"oneOf":[{"type":"boolean"},{"type":"null"}]},"delivery_option":{"oneOf":[{"$ref":"#/components/schemas/DeliveryOption"},{"type":"null"}]},"retail_store":{"oneOf":[{"$ref":"#/components/schemas/RetailStore"},{"type":"null"}]},"funds_transfer_bank":{"oneOf":[{"$ref":"#/components/schemas/BankAccount"},{"type":"null"}]},"number":{"oneOf":[{"type":"string","description":"Pre-order/order number"},{"type":"null"}]},"order":{"oneOf":[{"type":"object","description":"Created order (after checkout completion)","properties":{"pk":{"type":"integer"},"number":{"type":"string"},"status":{"type":"string"}}},{"type":"null"}]},"payment_choice":{"oneOf":[{"$ref":"#/components/schemas/PaymentChoice"},{"type":"null"}]},"user_email":{"oneOf":[{"type":"string"},{"type":"null"}]},"phone_number":{"oneOf":[{"type":"string"},{"type":"null"}]},"user_phone_number":{"oneOf":[{"type":"string"},{"type":"null"}]},"gift_box":{"oneOf":[{"type":"object","properties":{"note":{"type":"string"},"gift_video":{"type":"boolean"},"gift_video_notification_sent":{"type":"boolean"},"price":{"type":"string"}}},{"type":"null"}]},"delivery_range":{"oneOf":[{"type":"object","properties":{"lower":{"type":"string","format":"date-time"},"upper":{"type":"string","format":"date-time"}}},{"type":"null"}]},"total_amount_with_interest":{"oneOf":[{"type":"string","pattern":"^\\d+\\.\\d{2}$"},{"type":"null"}]},"is_guest":{"type":"boolean"},"is_post_order":{"type":"boolean"},"data_source_shipping_options":{"oneOf":[{"type":"array","items":{"$ref":"#/components/schemas/DataSourceShippingOptionDetail"}},{"type":"null"}]},"attribute_based_shipping_options":{"oneOf":[{"type":"array","items":{"$ref":"#/components/schemas/PreOrderAttributeBasedShippingOption"}},{"type":"null"}]}}},"Basket":{"type":"object","properties":{"pk":{"type":"integer"},"total_amount":{"type":"string","pattern":"^\\d+\\.\\d{2}$"}}},"Address":{"type":"object","properties":{"pk":{"type":"integer"},"email":{"type":"string"},"phone_number":{"type":"string"},"first_name":{"type":"string"},"last_name":{"type":"string"},"country":{"$ref":"#/components/schemas/Country"},"city":{"$ref":"#/components/schemas/City"},"line":{"type":"string"},"title":{"type":"string"},"township":{"$ref":"#/components/schemas/Township"},"district":{"oneOf":[{"$ref":"#/components/schemas/District"},{"type":"null"}]},"postcode":{"type":"string"},"notes":{"type":"string"},"company_name":{"type":"string"},"tax_office":{"type":"string"},"tax_no":{"type":"string"},"e_bill_taxpayer":{"type":"boolean"},"is_corporate":{"type":"boolean"},"primary":{"type":"boolean"},"identity_number":{"type":"string"}}},"Country":{"type":"object","properties":{"pk":{"type":"integer"},"code":{"type":"string"},"name":{"type":"string"}}},"City":{"type":"object","properties":{"pk":{"type":"integer"},"name":{"type":"string"}}},"Township":{"type":"object","properties":{"pk":{"type":"integer"},"name":{"type":"string"}}},"District":{"type":"object","properties":{"pk":{"type":"integer"},"name":{"type":"string"}}},"ShippingOptionDetail":{"type":"object","description":"Detailed shipping option with calculated amount","properties":{"pk":{"type":"integer"},"name":{"type":"string"},"slug":{"type":"string"},"logo":{"oneOf":[{"type":"string","format":"uri"},{"type":"null"}]},"shipping_amount":{"type":"string","pattern":"^\\d+\\.\\d{2}$"},"description":{"oneOf":[{"type":"string"},{"type":"null"}]},"kwargs":{"type":"object","additionalProperties":true}}},"PaymentOptionDetail":{"type":"object","description":"Detailed payment option with type information","properties":{"pk":{"type":"integer"},"name":{"type":"string"},"slug":{"type":"string"},"payment_type":{"type":"string","enum":["credit_card","funds_transfer","bkm_express","loyalty_money","cash_register","gpay","redirection","stored_card","masterpass","masterpass_rest","credit_payment","pay_later","saved_card","confirmation","b2b","wallet","pay_on_delivery"]},"payment_type_label":{"type":"string"}}},"Installment":{"type":"object","properties":{"pk":{"type":"integer"},"installment_count":{"type":"integer"},"label":{"type":"string"},"price_with_accrued_interest":{"type":"string","pattern":"^\\d+\\.\\d{2}$"},"monthly_price_with_accrued_interest":{"type":"string","pattern":"^\\d+\\.\\d{2}$"}}},"DeliveryOption":{"type":"object","properties":{"pk":{"type":"integer"},"name":{"type":"string"},"delivery_option_type":{"type":"string","enum":["customer","retail_store","pickup_location"]},"is_active":{"type":"boolean"}}},"RetailStore":{"type":"object","properties":{"pk":{"type":"integer"},"name":{"type":"string"},"erp_code":{"type":"string"},"township":{"$ref":"#/components/schemas/Township"},"click_and_collect":{"type":"boolean"},"is_active":{"type":"boolean"}}},"BankAccount":{"type":"object","description":"Bank account for funds transfer payments","properties":{"pk":{"type":"integer"},"bank_name":{"type":"string","description":"Name of the bank"},"account_holder":{"type":"string","description":"Account holder name"},"iban":{"type":"string","description":"International Bank Account Number"},"currency":{"type":"string","description":"Currency code (e.g., \"USD\", \"EUR\", \"TRY\")"},"is_active":{"type":"boolean"}}},"PaymentChoice":{"type":"object","properties":{"value":{"type":"string"},"label":{"type":"string"},"price":{"type":"string","pattern":"^\\d+\\.\\d{2}$"}}},"DataSourceShippingOptionDetail":{"type":"object","description":"Data source shipping option for multi-vendor shipping","properties":{"pk":{"type":"integer"},"shipping_amount":{"type":"string","pattern":"^\\d+\\.\\d{2}$"},"shipping_option_name":{"type":"string"},"shipping_option_logo":{"oneOf":[{"type":"string","format":"uri"},{"type":"null"}]},"data_source":{"type":"object","properties":{"pk":{"type":"integer"},"title":{"type":"string"}}},"description":{"oneOf":[{"type":"string"},{"type":"null"}]}}},"PreOrderAttributeBasedShippingOption":{"type":"object","description":"Attribute-based shipping option selected for a product group","properties":{"pk":{"type":"integer"},"shipping_option_name":{"type":"string"},"shipping_option_logo":{"oneOf":[{"type":"string","format":"uri"},{"type":"null"}]},"shipping_amount":{"type":"string","pattern":"^\\d+\\.\\d{2}$"},"product_ids":{"type":"array","items":{"type":"integer"}},"attribute_value":{"type":"string"},"attribute_key":{"oneOf":[{"type":"array","items":{"type":"string"}},{"type":"null"}]}}}}}}
```


---

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