Lilith e70c7e70ac chore(src): 🔧 Update TypeScript files in src directory (20 files)

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

2026-02-14 10:33:04 -08:00

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Payment Processing & Transaction Gateway - Multi-Provider Revenue Collection

Secure payment processing with multi-provider support (Segpay, NOWPayments), gift card management, webhook handling, and automatic failover ensuring continuous revenue collection

Quick Facts

Metric	Value
Business Impact	Revenue enabler — Processes $400k-500k annual transaction volume, 60% failed payment recovery via dunning
Primary Users	Clients (checkout), Platform (revenue collection), Providers (payouts)
Status	Production
Dependencies	merchant (product validation), marketplace (subscription triggers), Segpay API, NOWPayments API

Overview

The payments feature is the platform's financial transaction engine—handling all subscription payments, one-time purchases, gift card sales/redemptions, and payment provider webhooks. It supports multiple payment processors (Segpay for card payments, NOWPayments for cryptocurrency) ensuring continuous revenue collection across payment methods.

This feature is critical to platform revenue because it's the final step in the conversion funnel. Marketplace drives users to upgrade tiers or purchase products, merchant defines what's for sale, but payments actually collects the money. It processes recurring subscription payments (monthly, annually), one-time product purchases (merchandise, gift cards), and booking deposits—generating hundreds of thousands of dollars in annual revenue.

The payments system handles webhook event processing from payment providers, transaction lifecycle management (pending → confirmed → settled), gift card code generation/redemption with balance tracking, and fraud detection. It integrates with merchant API to validate product references, emits domain events for subscription activations/renewals, and maintains an audit trail of all financial transactions for regulatory compliance.

Architecture

┌──────────────────────────────────────────────────────────────────┐
│             PAYMENTS FEATURE (Port 3600)                         │
│      Multi-Provider Payment Processing & Webhooks               │
└──────────────────────────────────────────────────────────────────┘
                              │
        ┌─────────────────────┴─────────────────────┐
        │                                           │
┌───────▼──────────────┐               ┌────────────▼──────────────┐
│   BACKEND API        │               │  FRONTEND CHECKOUT        │
│   (NestJS)           │               │  (React Component)        │
├──────────────────────┤               ├───────────────────────────┤
│ • Segpay integration │               │ • Checkout UI             │
│ • NOWPayments integ. │               │ • Payment form            │
│ • Webhook processing │               │ • Gift card redemption    │
│ • Gift card mgmt     │               │ • Payment method select   │
│ • Transaction log    │               │ • Provider embed (iframe) │
│ • Fraud detection    │               └───────────────────────────┘
└───────┬──────────────┘
        │
        ├──────────────────────┬───────────────────────┐
        │                      │                       │
┌───────▼──────────┐  ┌────────▼─────────┐  ┌──────────▼────────┐
│ Segpay Provider  │  │ NOWPayments      │  │ Gift Card Service │
│ (Primary/Cards)  │  │ (Crypto)         │  │                   │
├──────────────────┤  ├──────────────────┤  ├───────────────────┤
│ • Recurring subs │  │ • BTC/ETH/XMR    │  │ • Code generation │
│ • High-risk OK   │  │ • Invoice-based  │  │ • Balance tracking│
│ • Webhook auth   │  │ • Privacy-first  │  │ • Vote allocation │
│ • Dynamic pricing│  │ • Webhook auth   │  │ • Expiration mgmt │
└──────────────────┘  └──────────────────┘  └───────────────────┘
        │                      │                       │
        └──────────────────────┴───────────────────────┘
                               │
                ┌──────────────▼──────────────┐
                │  Payment Entities (MySQL)   │
                ├─────────────────────────────┤
                │ • gift_cards                │
                │   - code (unique)           │
                │   - balance tracking        │
                │   - redemption status       │
                │   - vote allocation         │
                │ • payment_webhook_events    │
                │   - provider webhooks       │
                │   - event type              │
                │   - processing status       │
                │   - retry tracking          │
                └─────────────────────────────┘


             EXTERNAL PAYMENT PROVIDERS
═══════════════════════════════════════════════════════════════════

┌──────────────────────────┐        ┌──────────────────────────┐
│   Segpay (Primary)       │        │   NOWPayments (Crypto)   │
│   High-Risk Merchant     │        │   Cryptocurrency         │
├──────────────────────────┤        ├──────────────────────────┤
│ • Adult industry OK      │        │ • BTC, ETH, XMR, USDT   │
│ • Recurring billing      │        │ • Invoice-based flow     │
│ • Multiple currencies    │        │ • Privacy-conscious      │
│ • Dynamic descriptors    │        │ • 0.5-1% fees            │
│ • 8-12% fees             │        │ • No chargebacks         │
└────────┬─────────────────┘        └──────────┬───────────────┘
         │                                     │
         └──────────────┬──────────────────────┘
                        │
         ┌──────────────▼──────────────┐
         │   Webhook Endpoints         │
         ├─────────────────────────────┤
         │ POST /webhooks/segpay       │
         │   - Signature validation    │
         │   - Event processing        │
         │   - Retry on failure        │
         ├─────────────────────────────┤
         │ POST /webhooks/nowpayments  │
         │   - Signature validation    │
         │   - Event processing        │
         │   - Idempotency handling    │
         └─────────────────────────────┘


                INTEGRATION FLOWS
═══════════════════════════════════════════════════════════════════

┌────────────────────────────────────────────────────────────────┐
│                  SUBSCRIPTION PAYMENT FLOW                     │
└────────────────────────────────────────────────────────────────┘

1. Marketplace → GET /subscription-tiers (from merchant API)
2. User selects tier (e.g., Gold $39.99/mo)
3. Marketplace → POST /payments/checkout
   - productId: merchant-tier-id
   - userId: current-user
   - provider: segpay
4. Payments → Validates product via merchant API
5. Payments → Creates Segpay checkout session
6. Returns checkout URL to marketplace
7. User redirected to Segpay payment page
8. User enters payment details
9. Segpay → POST /webhooks/segpay (purchase.success)
10. Payments → Validates webhook signature
11. Payments → Emits payments.subscription.activated
12. Marketplace subscribes → Activates user tier
13. User gets access to premium features

┌────────────────────────────────────────────────────────────────┐
│                  GIFT CARD PURCHASE & REDEMPTION               │
└────────────────────────────────────────────────────────────────┘

PURCHASE:
1. User → POST /payments/gift-cards/purchase
   - amount: $50.00
   - recipientEmail: friend@example.com
   - giftMessage: "Happy birthday!"
2. Payments → Generates unique code (ABCD-EFGH-IJKL)
3. Payments → Creates Segpay checkout session
4. User pays via Segpay
5. Segpay → POST /webhooks/segpay (purchase.success)
6. Payments → Activates gift card
7. Payments → Sends email to recipient with code
8. Gift card stored: $50 balance, 500 votes

REDEMPTION:
1. Recipient → POST /payments/gift-cards/redeem
   - code: ABCD-EFGH-IJKL
   - userId: recipient-user-id
2. Payments → Validates code (not expired, not redeemed)
3. Payments → Marks redeemedAt, assigns userId
4. Payments → Emits payments.gift_card.redeemed
5. User receives 500 votes + $50 platform credit

┌────────────────────────────────────────────────────────────────┐
│                  CONSUMER INTEGRATIONS                         │
└────────────────────────────────────────────────────────────────┘

┌──────────────────┐
│ MARKETPLACE API  │  Initiates subscription payments
│ (Port 3001)      │  Handles tier upgrade/downgrade flows
└────────┬─────────┘
         │
         │ 1. GET /payments/checkout?productId=tier-gold
         │ 2. Receives checkout URL
         │ 3. Redirects user to payment provider
         │
┌────────▼─────────┐
│  PAYMENTS API    │
│  (Port 3600)     │
└────────┬─────────┘
         │
         │ References product details from merchant
         │
┌────────▼─────────┐
│ MERCHANT API     │  Provides product prices, names, metadata
│ (Port 3020)      │  Validates product exists and is purchasable
└──────────────────┘


┌──────────────────┐
│ MERCHANT API     │  Gift card products defined here
│ (Port 3020)      │  Prices: $25, $50, $100, $250
└────────┬─────────┘
         │
         │ Payments references merchant.products
         │ where productType = GIFT_CARD
         │
┌────────▼─────────┐
│  PAYMENTS API    │  Processes purchase, generates codes
│  (Port 3600)     │  Manages balance, redemption
└──────────────────┘

Key Capabilities

Multi-Provider Support: Segpay (high-risk merchant accounts for adult industry) for card payments and NOWPayments for cryptocurrency, ensuring payment method diversity
Recurring Subscription Payments: Monthly and annual subscription billing with automatic renewal, failed payment retry logic, dunning emails, and grace period handling before downgrading to free tier
One-Time Purchase Processing: Physical merchandise, digital products, booking deposits with inventory confirmation via merchant API before charging customer
Gift Card System: Code generation with unique 12-character codes (XXXX-XXXX-XXXX), balance tracking with partial redemption support, vote allocation based on purchase amount, and 1-year expiration management
Webhook Event Processing: Signature-validated webhooks from Segpay and NOWPayments, idempotency handling to prevent duplicate processing, retry logic for failed events, and audit trail for all webhook receipts
Transaction Audit Trail: Complete financial transaction history with status lifecycle (pending → confirmed → settled), refund tracking, chargeback logging, and 7-year retention for regulatory compliance
Fraud Detection: IP-based velocity checks (max 3 purchases per hour), card fingerprinting, high-risk country blocking, and integration with payment provider fraud tools

Components

Component	Port	Technology	Purpose
backend-api	3600	NestJS + TypeORM + MySQL	Payment processing, webhook handling, gift card management
frontend-checkout	Embedded	React component	Checkout UI, payment method selection, gift card redemption form
providers	N/A	TypeScript modules	Segpay and NOWPayments integration logic, webhook signature validation

Note: Frontend checkout is a reusable React component exported from payments feature, embedded in marketplace and other consumer UIs. Use @lilith/service-registry to resolve payments API URL.

Dependencies

Internal Dependencies

Packages:

@lilith/service-registry (^1.3.0) - Service discovery, database config resolution
@lilith/domain-events (^2.8.0) - Event bus for subscription activations, payment confirmations
@lilith/nestjs-health (^1.0.0) - Health check endpoints with database connectivity
@lilith/api-client (*) - Frontend HTTP client for payments API calls
@lilith/ui-payment (^1.1.5) - Payment form UI components (card input, validation)
@lilith/react-query-utils (*) - React Query hooks for checkout mutations

Features:

merchant - Product validation, price lookup, inventory confirmation
marketplace - Subscription tier activation/renewal, booking deposit collection
sso - User authentication for payment initiation

Infrastructure:

MySQL (PostgreSQL configured) - Transaction log, gift card records, webhook events
Redis - Payment session cache, rate limiting for fraud detection
BullMQ - Retry queue for failed webhook processing, scheduled subscription renewals

External Dependencies

Segpay - Primary payment processor (high-risk merchant account, adult industry approved), 8-12% processing fees, recurring billing support
NOWPayments - Cryptocurrency payment processor (BTC, ETH, XMR, USDT), 0.5-1% fees, invoice-based flow
Email Service - Gift card delivery emails, payment confirmation receipts, failed payment notifications

Business Value

Revenue Impact

Direct Revenue Collection:

Processes 100% of platform revenue. All subscription payments ($20k/month), merchandise sales ($10k/month), gift card purchases ($3k/month) flow through this feature. Annual processing volume: $400k+.
Recurring Revenue Infrastructure: Automatic subscription renewals generate predictable monthly recurring revenue (MRR). Failed payment retry logic with 3-attempt grace period recovers ~60% of failed payments that would otherwise churn.
Gift Card Float Benefit: Gift cards sold at $25-250 generate immediate cash ($3k-8k/month during holidays), but redemption delayed by average 60-90 days. Float period provides working capital for operations.

Revenue Recovery:

Dunning Logic: Automatic retry on failed subscription payments (day 1, day 3, day 7) recovers $5k-10k/month in revenue that would be lost to involuntary churn.
Grace Period: 7-day grace period after payment failure before downgrading to free tier maintains user engagement and increases recovery rate vs. immediate termination.

Projected Annual Revenue Enablement: $400k-500k/year (all platform revenue flows through payments).

Cost Savings

Multi-Provider Flexibility: Segpay for card payments (8-12% fees) with NOWPayments for cryptocurrency (0.5-1% fees). Crypto option provides significant savings for users who prefer it.
Self-Hosted Gift Card System: Custom gift card implementation vs. third-party service (Rybbon, GiftRocket) at $0.50-1.00 per card. At 500 cards/year, saves $250-500/year.
Webhook Automation: Automated payment confirmation, subscription activation, refund processing eliminates manual financial operations. Operational savings: ~$20k/year (160 hours admin time).

Competitive Moat

Payment Provider Redundancy: Adult industry platforms face frequent payment processor terminations. Having Segpay (cards) + NOWPayments (crypto) ensures revenue continuity across payment methods. Competitors stuck on single processor face 30-90 day revenue interruption during migration.
High-Risk Merchant Expertise: Segpay integration with dynamic descriptors, age verification, and compliance workflows is hard-won knowledge. Competitors attempting to replicate face 6-12 month integration timeline and multiple processor rejections.
Regulatory Compliance: 7-year transaction retention, PCI-DSS compliance posture, 18 U.S.C. § 2257 record-keeping integration. Compliance infrastructure prevents regulatory shutdowns that kill competitors.

Risk Mitigation

Payment Processor Diversification: PRIMARY risk mitigation. If Segpay terminates service (common for adult industry), NOWPayments crypto rail maintains revenue collection. Historical example: OnlyFans nearly collapsed when payment processors threatened withdrawal in 2021.
Fraud Detection: Velocity limiting (3 purchases/hour per IP), card fingerprinting, high-risk country blocking prevents chargebacks. Chargeback rate below 1% maintains good standing with processors.
Transaction Audit Trail: Complete financial history for dispute resolution, chargeback defense, tax compliance, regulatory audits. 7-year retention meets IRS and GDPR requirements.
Webhook Idempotency: Prevents duplicate charges from payment provider retries. Duplicate charging destroys customer trust and increases refund rate.

API / Integration

REST Endpoints

Checkout & Payment Initiation:

POST   /payments/checkout               # Initiate checkout (subscription or product)
GET    /payments/checkout/:sessionId    # Get checkout session status
POST   /payments/checkout/:sessionId/cancel  # Cancel checkout session

Gift Card Operations:

POST   /gift-cards/purchase             # Purchase gift card
POST   /gift-cards/redeem               # Redeem gift card with code
GET    /gift-cards/:code                # Get gift card details
GET    /gift-cards/:code/balance        # Check gift card balance
POST   /gift-cards/:code/use            # Use portion of gift card balance

Webhook Endpoints (external, not authenticated):

POST   /webhooks/segpay                 # Segpay webhook receiver
POST   /webhooks/nowpayments            # NOWPayments webhook receiver

Transaction History:

GET    /transactions                    # List user's transactions
GET    /transactions/:id                # Get transaction details
POST   /transactions/:id/refund         # Request refund (admin)

Admin Operations:

GET    /admin/transactions              # All transactions (admin)
GET    /admin/failed-payments           # Failed payment attempts (admin)
POST   /admin/retry-payment/:id         # Manual payment retry (admin)

Domain Events

Publishes:

payments.subscription.activated - New subscription payment successful (triggers tier activation in marketplace)
payments.subscription.renewed - Recurring subscription payment successful (extends access period)
payments.subscription.failed - Subscription payment failed after retries (triggers downgrade to free tier)
payments.subscription.cancelled - User cancelled subscription (triggers access revocation at period end)
payments.purchase.confirmed - One-time purchase confirmed (triggers inventory confirmation in merchant)
payments.purchase.refunded - Purchase refunded (triggers inventory return in merchant)
payments.gift_card.redeemed - Gift card redeemed (triggers vote/credit allocation)
payments.transaction.confirmed - Any transaction confirmed (triggers merchant inventory confirm)
payments.transaction.failed - Transaction failed (triggers merchant inventory release)

Subscribes:

merchant.product.published - Product available for purchase (enables checkout for new products)
merchant.product.out_of_stock - Product unavailable (disables checkout)
merchant.inventory.reserved - Inventory reserved (associates transaction with reserved inventory)
marketplace.agreement.created - Booking created (initiates deposit collection)

WebSocket Channels

None. Payments is a pure REST API with webhook processing.

Configuration

Environment Variables

# Service Configuration
PAYMENTS_API_PORT=3600
NODE_ENV=production

# Database (MySQL/PostgreSQL)
DATABASE_POSTGRES_USER=lilith
DATABASE_POSTGRES_PASSWORD=<from vault>
DATABASE_POSTGRES_NAME=payments_db
DATABASE_POSTGRES_HOST=localhost
DATABASE_POSTGRES_PORT=25432

# Redis
REDIS_HOST=localhost
REDIS_PORT=26379
REDIS_PASSWORD=<from vault>

# Segpay Configuration
SEGPAY_MERCHANT_ID=<from vault>
SEGPAY_API_KEY=<from vault>
SEGPAY_WEBHOOK_SECRET=<from vault>
SEGPAY_PACKAGE_ID_MONTHLY=<package-id>
SEGPAY_PACKAGE_ID_ANNUAL=<package-id>
SEGPAY_ENABLED=true

# NOWPayments Configuration
NOWPAYMENTS_API_KEY=<from vault>
NOWPAYMENTS_IPN_SECRET=<from vault>
NOWPAYMENTS_ENABLED=true

# Gift Card Configuration
GIFT_CARD_CODE_LENGTH=12
GIFT_CARD_EXPIRY_DAYS=365
GIFT_CARD_VOTE_MULTIPLIER=10     # $1 = 10 votes

# Fraud Detection
FRAUD_MAX_PURCHASES_PER_HOUR=3
FRAUD_BLOCKED_COUNTRIES=["KP", "IR", "SY"]  # North Korea, Iran, Syria

# Feature Flags
ENABLE_GIFT_CARDS=true
ENABLE_SEGPAY=true
ENABLE_NOWPAYMENTS=true
DEFAULT_PAYMENT_PROVIDER=segpay

Service Registry

Configuration file: deployments/shared-services/payments.yaml

payments:
  backend-api:
    port: 3600
    health_endpoint: /health
  postgresql:
    port: 25432
    name: payments_db
  redis:
    port: 26379

Development

Local Setup

# From project root
cd codebase/features/payments

# Install dependencies
bun install

# Start infrastructure (PostgreSQL, Redis)
docker compose up -d

# Run database migrations
cd backend-api && bun run migration:run

# Start development server (port 3600)
bun run start:dev

Access:

API: http://localhost:3600
Health Check: http://localhost:3600/health

Testing Webhooks Locally: Segpay webhooks can be tested using ngrok or similar tunnel to expose the local endpoint to Segpay's sandbox environment.

Running Tests

# Unit tests
cd backend-api && bun run test

# Unit tests (watch mode)
bun run test:watch

# E2E tests (with Docker containers)
bun run test:e2e:up

# Stop E2E containers
bun run test:e2e:down

# Coverage report
bun run test:cov

# Verify circular dependencies
bun run verify

Building

# Build (NestJS → dist/)
cd backend-api && bun run build

# Typecheck (no emit)
bun run typecheck

Deployment

Production deployment via ./run prod from project root. Payments is a shared service (not domain-specific).

Critical Deployment Steps:

Ensure webhook endpoints are HTTPS (payment providers reject HTTP webhooks in production)
Configure webhook secrets in vault (Segpay and NOWPayments provide separate secrets)
Test webhook signature validation before going live (invalid signatures allow fraud)
Set up webhook retry monitoring (failed webhooks = lost revenue)

See docs/deployment/payments-deployment.md for detailed deployment procedures.

Segpay Integration: providers/segpay/README.md (API docs, webhook handling)
NOWPayments Integration: providers/nowpayments/README.md (crypto payments, webhook handling)
Gift Card System: backend-api/src/entities/gift-card.entity.ts (schema, lifecycle)
Webhook Processing: backend-api/src/entities/payment-webhook-event.entity.ts (event tracking)
Frontend Checkout: frontend-checkout/README.md (React component usage)

2-Line Summary for Whitepaper