> ## Documentation Index > Fetch the complete documentation index at: https://docs.withflex.com/llms.txt > Use this file to discover all available pages before exploring further. # Create Coupon > Creates a coupon. Exactly one of `amount_off` or `percent_off` must be provided; supplying both, or neither, is rejected. When `duration` is `repeating`, `duration_in_months` is required. ## OpenAPI ````yaml /openapi.json post /v1/coupons openapi: 3.1.0 info: title: Flex API description: >- The Flex API powers HSA/FSA payment processing for healthcare commerce: checkout sessions, payment intents, subscriptions, customers, refunds, disputes, and eligibility. Authenticate with your partner API key as a Bearer token. All endpoints are scoped to your partner account, and test mode is fully supported via test API keys. version: 0.1.0 servers: - url: https://api.withflex.com security: - BearerAuth: [] tags: - name: Balance Transactions - name: Captures - name: Checkout Sessions - name: Coupons - name: Customers - name: Disputes - name: Events - name: Exports - name: Files - name: Invoices - name: Letters - name: Orders - name: Payment Intents - name: Payment Links - name: Payouts - name: Prices - name: Products - name: Promo Codes - name: Receipts - name: Refunds - name: Setup Intents - name: Shipping Rates - name: Subscriptions paths: /v1/coupons: post: tags: - Coupons summary: Create Coupon description: >- Creates a coupon. Exactly one of `amount_off` or `percent_off` must be provided; supplying both, or neither, is rejected. When `duration` is `repeating`, `duration_in_months` is required. operationId: v1.coupons.create requestBody: description: An envelope wrapping a single coupon object. content: application/json: schema: $ref: '#/components/schemas/CouponBody_for_CreateCouponRequest' example: coupon: name: Coupon amount_off: 100 duration: once percent_off: 10 max_redemptions: 100 metadata: key: value required: true responses: '200': description: An envelope wrapping a single coupon object. content: application/json: schema: $ref: '#/components/schemas/CouponBody_for_V1Coupon' example: coupon: coupon_id: fcoup_1234567890 amount_off: 2500 duration: once metadata: order_id: '8842' channel: shopify name: Example valid: false created_at: '2026-06-15T14:30:00Z' test_mode: false '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/HttpErrorOut' example: code: string detail: string '403': description: Forbidden content: application/json: schema: $ref: '#/components/schemas/HttpErrorOut' example: code: string detail: string '404': description: Not Found content: application/json: schema: $ref: '#/components/schemas/HttpErrorOut' example: code: string detail: string '409': description: Conflict content: application/json: schema: $ref: '#/components/schemas/HttpErrorOut' example: code: string detail: string '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' example: detail: - loc: - string msg: string type: string '429': description: Too Many Requests content: application/json: schema: $ref: '#/components/schemas/HttpErrorOut' example: code: string detail: string security: - BearerAuth: - coupons:write components: schemas: CouponBody_for_CreateCouponRequest: description: An envelope wrapping a single coupon object. type: object required: - coupon properties: coupon: $ref: '#/components/schemas/CreateCouponRequest' description: The coupon. example: coupon: name: Coupon amount_off: 100 duration: once percent_off: 10 max_redemptions: 100 metadata: key: value CouponBody_for_V1Coupon: description: An envelope wrapping a single coupon object. type: object required: - coupon properties: coupon: $ref: '#/components/schemas/V1Coupon' description: The coupon. example: coupon: coupon_id: fcoup_1234567890 amount_off: 2500 duration: once metadata: order_id: '8842' channel: shopify name: Example valid: false created_at: '2026-06-15T14:30:00Z' test_mode: false HttpErrorOut: title: HttpError description: The error response returned when a request cannot be completed. type: object required: - code - detail properties: code: description: A short machine-readable error code identifying the type of error. type: string detail: description: A human-readable explanation of what went wrong. type: string example: code: string detail: string HTTPValidationError: description: The error response returned when request validation fails (HTTP 422). type: object required: - detail properties: detail: description: The list of validation errors, one entry per invalid field. type: array items: $ref: '#/components/schemas/ValidationErrorItem' example: detail: - loc: - string msg: string type: string CreateCouponRequest: description: >- Parameters for creating a coupon. Exactly one of `amount_off` or `percent_off` must be set. type: object required: - name properties: applies_to: description: >- An object containing directions for what this Coupon will apply discounts to. If null, the coupon applies to the entire order. anyOf: - $ref: '#/components/schemas/AppliesTo' - type: 'null' name: description: Name of the coupon displayed to customers. type: string example: Coupon amount_off: description: >- A positive integer representing the amount to subtract from an invoice total (required if percent_off is not passed). type: - integer - 'null' format: int32 example: 100 duration: description: >- Specifies how long the discount will be in effect if used on a subscription. Defaults to once. anyOf: - $ref: '#/components/schemas/CouponDuration' - type: 'null' example: once duration_in_months: description: >- Required only if duration is repeating, in which case it must be a positive integer that specifies the number of months the discount will be in effect. type: - integer - 'null' format: int32 example: null percent_off: description: >- A positive float larger than 0, and smaller or equal to 100, that represents the discount the coupon will apply (required if amount_off is not passed). type: - number - 'null' format: double example: 10 max_redemptions: description: >- A positive integer specifying the number of times the coupon can be redeemed before it’s no longer valid. type: - integer - 'null' format: int32 example: 100 metadata: description: Metadata to attach to this coupon. type: - object - 'null' example: key: value example: applies_to: products: [] name: Coupon amount_off: 100 duration: once percent_off: 10 max_redemptions: 100 metadata: key: value V1Coupon: description: >- A coupon contains information about a percent-off or amount-off discount you might want to apply to a customer. Coupons may be applied to subscriptions and checkout sessions. type: object required: - coupon_id - created_at - duration - name - test_mode - valid properties: coupon_id: description: Unique identifier for the object. type: string example: fcoup_1234567890 amount_off: description: >- Amount that will be taken off the subtotal of any invoices for this customer. type: - integer - 'null' format: int32 example: 2500 applies_to: description: >- An object containing the ID of the product that the coupon can be applied to. anyOf: - $ref: '#/components/schemas/AppliesTo' - type: 'null' duration: $ref: '#/components/schemas/CouponDuration' description: >- One of forever, once, and repeating. Describes how long a customer who applies this coupon will get the discount. duration_in_months: description: >- If duration is repeating, the number of months the coupon applies. Null if coupon duration is forever or once. type: - integer - 'null' format: int32 metadata: description: >- Set of key-value pairs that you can attach to an object. This can be useful for storing additional information about the object in a structured format. type: - object - 'null' example: order_id: '8842' channel: shopify name: description: Name of the coupon displayed to customers. type: string example: Example percent_off: description: >- Percent that will be taken off the subtotal of any invoices for this customer for the duration of the coupon. type: - number - 'null' format: double max_redemptions: description: >- Maximum number of times this coupon can be redeemed, in total, across all customers, before it is no longer valid. type: - integer - 'null' format: int32 times_redeemed: description: Number of times this coupon has been applied to a customer. type: - integer - 'null' format: int32 valid: description: >- Taking account of the above properties, whether this coupon can still be applied to a customer. type: boolean example: false created_at: $ref: '#/components/schemas/Timestamptz' description: Date when this coupon was created. example: '2026-06-15T14:30:00Z' test_mode: description: Whether the coupon is in test mode type: boolean example: false example: coupon_id: fcoup_1234567890 amount_off: 2500 applies_to: products: [] duration: once metadata: order_id: '8842' channel: shopify name: Example valid: false created_at: '2026-06-15T14:30:00Z' test_mode: false ValidationErrorItem: description: >- Validation errors have their own schema to provide context for invalid requests eg. mismatched types and out of bounds values. There may be any number of these per 422 UNPROCESSABLE ENTITY error. type: object required: - loc - msg - type properties: loc: description: >- The location as a [`Vec`] of [`String`]s -- often in the form `["body", "field_name"]`, `["query", "field_name"]`, etc. They may, however, be arbitarily deep. type: array items: type: string msg: description: The message accompanying the validation error item. type: string type: description: >- The type of error, often "type_error" or "value_error", but sometimes with more context like as "value_error.number.not_ge" type: string example: loc: - string msg: string type: string AppliesTo: description: What a coupon's discount is restricted to. anyOf: - type: object required: - products properties: products: description: The product that this coupon applies to. type: array items: type: string example: fprod_01J9XR8M3K7VZ8N2YB4WJ6T0RA - type: object required: - prices properties: prices: description: The price that this coupon applies to. type: array items: type: string example: fprice_01J9XR8M3K7VZ8N2YB4WJ6T0RA - type: object required: - fee_types properties: fee_types: description: The fee types that this coupon applies to. type: array items: $ref: '#/components/schemas/FeeType' - $ref: '#/components/schemas/AppliesToShipping' example: products: - fprod_01J9XR8M3K7VZ8N2YB4WJ6T0RA CouponDuration: type: string enum: - once - repeating - forever x-ms-enum: name: CouponDuration modelAsString: false values: - value: once name: Once description: >- Applies to the first charge from a subscription with this coupon applied. - value: repeating name: Repeating description: >- Applies to charges in the first duration_in_months months from a subscription with this coupon applied. - value: forever name: Forever description: >- Applies to all charges from a subscription with this coupon applied. description: >- - `once`: Applies to the first charge from a subscription with this coupon applied. - `repeating`: Applies to charges in the first duration_in_months months from a subscription with this coupon applied. - `forever`: Applies to all charges from a subscription with this coupon applied. example: once Timestamptz: description: >- A timestamp encoded as an RFC 3339 / ISO 8601 string (e.g. `2026-06-15T14:30:00Z`). type: string example: string FeeType: description: >- The kind of fee applied to a checkout session: a Letter of Medical Necessity consultation fee, or a custom fee you define. type: string enum: - lmn_consultation - custom example: lmn_consultation AppliesToShipping: description: The coupon applies to shipping. type: string enum: - shipping example: shipping securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: API Key description: Use a Bearer token to access this API. ````