Overview The defineDiscount() function defines a discount or coupon code that customers can apply at checkout. It’s an identity function that provides type inference and autocomplete while returning the input as-is.
Function Signature function defineDiscount < T extends DiscountDef >( config : T ) : T
Type Parameters The discount configuration type. Must extend DiscountDef.
Parameters The discount configuration object. The code the user enters at checkout (e.g., ‘BLACKFRIDAY_24’, ‘LAUNCH50’).
Friendly name displayed on invoices and receipts.
type
'percent' | 'amount'
required
The type of discount:
percent: Percentage off (0-100)amount: Fixed amount off in smallest currency unit The discount value:
For percent: 0-100 (e.g., 25 = 25% off)
For amount: cents/smallest unit (e.g., 1000 = $10.00 off)
duration
'once' | 'forever' | 'repeating'
required
How long the discount lasts:
once: Applied to the first invoice onlyforever: Applied to every invoice indefinitelyrepeating: Applied for a specific number of months Required if duration === 'repeating'. Number of billing cycles to apply the discount.
Restrict discount to specific plan slugs. Empty or omitted means all plans.
Maximum number of times this code can be redeemed globally. Omit for unlimited.
Expiration date in ISO 8601 format (e.g., “2024-12-31T23:59:59Z”).
Returns The same configuration object passed in, with full type inference preserved.
Usage Percentage Discount - One Time import { defineDiscount } from "@revstack/core" ; export const welcome = defineDiscount ({ code: "WELCOME20" , name: "New Customer Welcome - 20% Off First Month" , type: "percent" , value: 20 , duration: "once" , max_redemptions: 1000 , expires_at: "2024-12-31T23:59:59Z" , });
Percentage Discount - Forever import { defineDiscount } from "@revstack/core" ; export const nonprofit = defineDiscount ({ code: "NONPROFIT50" , name: "Nonprofit/Education - 50% Off Forever" , type: "percent" , value: 50 , duration: "forever" , // No expiration for nonprofit discounts });
Percentage Discount - Repeating import { defineDiscount } from "@revstack/core" ; export const launch = defineDiscount ({ code: "LAUNCH50" , name: "Launch Special - 50% Off for 3 Months" , type: "percent" , value: 50 , duration: "repeating" , duration_in_months: 3 , max_redemptions: 100 , expires_at: "2024-06-30T23:59:59Z" , });
Fixed Amount Discount import { defineDiscount } from "@revstack/core" ; export const tenOff = defineDiscount ({ code: "SAVE10" , name: "$10 Off First Month" , type: "amount" , value: 1000 , // $10.00 in cents duration: "once" , max_redemptions: 500 , });
Plan-Specific Discount import { defineDiscount } from "@revstack/core" ; export const enterpriseTrial = defineDiscount ({ code: "ENTERPRISE_TRIAL" , name: "Enterprise Trial - 30% Off for 6 Months" , type: "percent" , value: 30 , duration: "repeating" , duration_in_months: 6 , applies_to_plans: [ "enterprise" ], // Only for enterprise plan });
Black Friday Campaign import { defineDiscount } from "@revstack/core" ; export const blackFriday = defineDiscount ({ code: "BLACKFRIDAY_2024" , name: "Black Friday 2024 - 40% Off Yearly Plans" , type: "percent" , value: 40 , duration: "once" , applies_to_plans: [ "pro" , "business" ], // Only yearly intervals max_redemptions: 250 , expires_at: "2024-11-30T23:59:59Z" , });
Partner/Referral Discount import { defineDiscount } from "@revstack/core" ; export const partner = defineDiscount ({ code: "PARTNER_ACME" , name: "Acme Corp Partnership - 25% Off Forever" , type: "percent" , value: 25 , duration: "forever" , // No max_redemptions for partner codes });
Complete Configuration import { defineConfig , defineDiscount } from "@revstack/core" ; export default defineConfig ({ features: { /* ... */ } , plans: { /* ... */ } , coupons: [ defineDiscount ({ code: "WELCOME20" , name: "Welcome - 20% Off" , type: "percent" , value: 20 , duration: "once" , max_redemptions: 1000 , }), defineDiscount ({ code: "LAUNCH50" , name: "Launch Special - 50% Off 3 Months" , type: "percent" , value: 50 , duration: "repeating" , duration_in_months: 3 , expires_at: "2024-12-31T23:59:59Z" , }), defineDiscount ({ code: "SAVE10" , name: "$10 Off" , type: "amount" , value: 1000 , duration: "once" , }), ] , }) ;
Discount Types Percentage Discount Reduces the price by a percentage:
{ type : "percent" , value : 25 , // 25% off } // $100/month plan → $75/month with discount
Amount Discount Reduces the price by a fixed amount:
{ type : "amount" , value : 1000 , // $10.00 off (in cents) } // $100/month plan → $90/month with discount
Duration Options Once Applied to the first invoice only:
{ duration : "once" } // Month 1: $80 (with 20% discount) // Month 2+: $100 (regular price)
Forever Applied to every invoice indefinitely:
{ duration : "forever" } // Every month: $80 (with 20% discount)
Repeating Applied for a specific number of billing cycles:
{ duration : "repeating" , duration_in_months : 3 , } // Months 1-3: $80 (with 20% discount) // Month 4+: $100 (regular price)
Best Practices Naming Conventions
Use uppercase for code (e.g., “LAUNCH50”, “SAVE10”)
Use descriptive names that include the offer (e.g., “Launch Special - 50% Off”)
Expiration
Always set expires_at for promotional campaigns
Omit expires_at for permanent partner/nonprofit codes
Redemption Limits
Set max_redemptions for limited-time promotions
Omit max_redemptions for evergreen codes
Plan Restrictions
Use applies_to_plans for plan-specific offers
Omit to allow discount on all plans
Source Location : packages/core/src/define.ts:88-90