Payment Configuration

The template supports multiple payment providers and flexible billing workflows. This reference covers every payment-related constant, enum, and configuration option.

Payment Constants

All core payment enums and types are defined in lib/constants/payment.ts. This file is intentionally kept separate from the main config module so it can be imported in scripts that run outside the Next.js runtime (migrations, seeds, CLI tools).

PaymentFlow

Determines when payment is collected relative to the submission process.

export enum PaymentFlow {
  PAY_AT_START = 'pay_at_start',
  PAY_AT_END = 'pay_at_end',
}

Value	Description
pay_at_start	User pays before submitting; item is published immediately
pay_at_end	User submits first; payment is collected after admin approval

PaymentStatus

Tracks the state of a payment attempt.

export enum PaymentStatus {
  PENDING = 'pending',
  PAID = 'paid',
  FAILED = 'failed',
}

PaymentInterval

Billing frequency options.

export enum PaymentInterval {
  DAILY = 'daily',
  WEEKLY = 'weekly',
  MONTHLY = 'monthly',
  YEARLY = 'yearly',
  ONE_TIME = 'one-time',
  PER_SUBMISSION = 'per-submission',
}

PaymentPlan

Available subscription tiers.

export enum PaymentPlan {
  FREE = 'free',
  STANDARD = 'standard',
  PREMIUM = 'premium',
}

PaymentProvider

Supported payment gateways.

export enum PaymentProvider {
  STRIPE = 'stripe',
  SOLIDGATE = 'solidgate',
  LEMONSQUEEZY = 'lemonsqueezy',
  POLAR = 'polar',
}

Payment Configuration Schema

Defined in lib/config/schemas/payment.schema.ts and validated at startup with Zod.

Product Pricing (Display Values)

pricing: {
  free: number;       // Default: 0
  standard: number;   // Default: 10
  premium: number;    // Default: 20
}

Env Var	Field	Default
NEXT_PUBLIC_PRODUCT_PRICE_FREE	pricing.free	0
NEXT_PUBLIC_PRODUCT_PRICE_STANDARD	pricing.standard	10
NEXT_PUBLIC_PRODUCT_PRICE_PREMIUM	pricing.premium	20

Trial Configuration

Env Var	Field	Description
NEXT_PUBLIC_STANDARD_TRIAL_AMOUNT_ID	trial.standardTrialAmountId	Price ID for standard trial
NEXT_PUBLIC_PREMIUM_TRIAL_AMOUNT_ID	trial.premiumTrialAmountId	Price ID for premium trial
NEXT_PUBLIC_AUTHORIZED_TRIAL_AMOUNT	trial.authorized	Enable trial amounts (true/false)

Provider Setup

Stripe

Auto-enabled when both secretKey and publishableKey are present.

Env Var	Required	Description
STRIPE_SECRET_KEY	Yes	Server-side API key
NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY	Yes	Client-side publishable key
STRIPE_WEBHOOK_SECRET	Recommended	Webhook signature verification
NEXT_PUBLIC_STRIPE_FREE_PRICE	No	Price ID for free plan
NEXT_PUBLIC_STRIPE_STANDARD_PRICE_ID	No	Price ID for standard plan
NEXT_PUBLIC_STRIPE_PREMIUM_PRICE_ID	No	Price ID for premium plan
NEXT_PUBLIC_STRIPE_DYNAMIC_PRICING	No	Set true to fetch prices from Stripe API

LemonSqueezy

Auto-enabled when both apiKey and storeId are present.

Env Var	Required	Description
LEMONSQUEEZY_API_KEY	Yes	API key from LemonSqueezy dashboard
LEMONSQUEEZY_STORE_ID	Yes	Your store identifier
LEMONSQUEEZY_WEBHOOK_SECRET	Recommended	Webhook signature verification
LEMONSQUEEZY_WEBHOOK_URL	No	Override webhook endpoint URL
LEMONSQUEEZY_TEST_MODE	No	Set true for test mode
LEMONSQUEEZY_VARIANT_ID	No	Default variant ID

Polar

Auto-enabled when both accessToken and organizationId are present.

Env Var	Required	Description
POLAR_ACCESS_TOKEN	Yes	API access token
POLAR_ORGANIZATION_ID	Yes	Organization identifier
POLAR_WEBHOOK_SECRET	Recommended	Webhook signature verification
POLAR_SANDBOX	No	Set false for production (default: true)
POLAR_API_URL	No	Override API base URL

Solidgate

Requires manual environment variable configuration.

Env Var	Required	Description
SOLIDGATE_API_KEY	Yes	API key
SOLIDGATE_SECRET_KEY	Yes	Secret key for signing
SOLIDGATE_WEBHOOK_SECRET	Yes	Webhook verification
SOLIDGATE_MERCHANT_ID	Yes	Merchant identifier
NEXT_PUBLIC_SOLIDGATE_PUBLISHABLE_KEY	No	Client-side key

Multi-Currency Billing

Each provider supports per-currency pricing via the billing config modules in lib/config/billing/.

Billing Config Types

type CurrencyCode = 'usd' | 'eur' | 'gbp' | 'cad';
type PlanName = 'premium' | 'standard' | 'free';

interface AmountConfig {
  monthly?: string;   // Price/variant ID for monthly billing
  yearly?: string;    // Price/variant ID for yearly billing
  setupFee?: string;  // Optional setup fee price ID
}

interface CurrencyConfig {
  amount: AmountConfig;
  currency?: string;  // ISO 4217 code (e.g., 'USD')
  symbol?: string;    // Display symbol (e.g., '$')
}

type PlanConfig = {
  productId: string | undefined;
} & Partial<Record<CurrencyCode, CurrencyConfig>>;

Supported Currencies

The SUPPORTED_CURRENCIES array in lib/config/billing/types.ts lists all 32 ISO 4217 codes accepted by the system (USD, EUR, GBP, JPY, CNY, CAD, AUD, CHF, and more).

Price Resolution Functions

Each provider exports a price config function:

Provider	Function	Source
Stripe	getStripePriceConfig(plan, currency, interval)	billing/stripe.config.ts
LemonSqueezy	getLemonSqueezyPriceConfig(plan, currency, interval)	billing/lemonsqueezy.config.ts
Polar	getPolarPriceConfig(plan, currency, interval)	billing/polar.config.ts

All functions fall back to USD if the requested currency is not configured.

Payment Flow Configuration

Defined in lib/config/payment-flows.ts, the PAYMENT_FLOWS array configures the two payment flow options with their UI properties:

interface PaymentFlowConfig {
  id: PaymentFlow;
  title: string;
  subtitle: string;
  description: string;
  icon: string;            // Lucide icon name
  color: string;           // Tailwind gradient classes
  features: string[];      // Feature bullet points
  benefits: Array<{ icon: string; text: string; color: string }>;
  badge?: string;          // Optional badge label
  isDefault?: boolean;     // Whether this is the default flow
}

Helper functions:

• getDefaultPaymentFlow() -- returns the default PaymentFlow value
• getPaymentFlowConfig(flowId) -- returns the PaymentFlowConfig for a given flow

Payment Provider Manager

The PaymentProviderManager class in lib/payment/config/payment-provider-manager.ts provides singleton access to provider instances:

// Get a specific provider
const stripe = PaymentProviderManager.getStripeProvider();
const ls = PaymentProviderManager.getLemonsqueezyProvider();
const polar = PaymentProviderManager.getPolarProvider();
const sg = PaymentProviderManager.getSolidgateProvider();

// Or use the generic function
import { getOrCreateProvider } from '@/lib/payment/config/payment-provider-manager';
const provider = getOrCreateProvider('stripe');

Related Pages

• Payment Types -- type definitions for payment operations
• Subscription Types -- subscription lifecycle types
• Environment Reference -- full environment variable listing