Prisma

JoyMini API — Enterprise-Level NestJS Backend Architecture Practice

A unified backend platform built with NestJS + Prisma + PostgreSQL + Redis + BullMQ, supporting 200+ API endpoints across 4 frontend applications

NestJS Sensitive Word Filtering: AC Automaton Pipe Implementation and Performance Optimization

The blog system's comment content uses the AC Automaton algorithm for sensitive word detection, integrated transparently as a NestJS Pipe. It covers a three-level sensitive word grading strategy, detection performance of < 1ms for a 100,000-word dictionary, a Redis hot-update mechanism, and a multi-layered defense design.

Next.js Blog Comment System: A Complete Architecture from AI Moderation to Optimistic Updates

Prisma v6 Migration Practice: Database Upgrade in a Monorepo

Prisma Optimistic Locking in Practice: Dual-Currency Wallet System with Audit Trail for Financial Tracking

An in-depth analysis of a production-grade NestJS wallet service, covering Prisma update where optimistic locking, dual-currency accounting (cash + coins), freeze/unfreeze mechanisms, and complete transaction flow tracking.

Order Payment Pipeline: Coupon + Flash Sale + Coins + Group Buy Four-Layer Price Calculation

An in-depth analysis of the `OrderService.checkOut` method in a NestJS project, demonstrating how to chain four layers of price calculation (flash sale, coupon, coins, group buy) and five subsystems within a Prisma transaction, covering optimistic lock debit, atomic inventory deduction, and a complete refund flow.

Financial Audit System: NestJS Xendit Payout + @DistributedLock + Cron Ghost Order Auto-Recovery

In-depth analysis of a production-grade financial audit system, covering distributed locks to prevent duplicate payouts, Xendit third-party payout integration, Cron auto-recovery mechanisms, and a complete state machine design.

LuckyDrawService Lottery System: Weighted Random + Atomic Ticket Engine

JoyMini's lottery system is based on a weighted random algorithm and Prisma atomic ticket operations, covering the complete transactional flow of prize pool management, ticket purchase, drawing, and prize redemption, ensuring data consistency under high concurrency.

Deep Dive into Payment Webhook & Callback Handling — Optimistic Locking, Idempotency, Atomic Wallet Operations

In-depth analysis of PaymentWebhookController (single endpoint routing + callback-token authentication) → handleUniversalWebhook (deposit/withdrawal routing) → handleInvoiceWebhook (updateMany optimistic locking + creditCash) → handlePayoutWebhook (atomic unfreeze + CRITICAL degradation) → WalletService (ensureWallet / creditCash / freezeCash / unfreezeCash + beforeBalance/afterBalance audit trail)

OTP & SMS Verification System — Pepper Hashing + DB Rate Limiting + State Machine + Replay Attack Protection

In-depth analysis of the NestJS OTP verification system: SmsVerificationCode model with 17-field state machine design, SHA-256 Pepper hashing for leak prevention, 60s DB rate limiting + 5-attempt lockout, concurrent safe updates, Throttler dual protection, and production/development dual modes.