ZenMoney — Personal Finance Management App

Overview

A personal app to manage cash flow aligned with a salary cycle (25th of each month), auto-allocate budget into specialized bank accounts, and track long-term investment portfolios.

Tech Stack

• •Runtime: NestJS 11 (TypeScript)
• •ORM: Prisma 7.2.0 with prisma-client-js generator
• •Database: PostgreSQL (local Prisma Postgres via prisma dev, connect via accelerateUrl)
• •Package manager: Yarn
• •Note: Prisma 7 requires accelerateUrl in PrismaClient constructor (no datasourceUrl/datasources)

Core Entities

Modules & Features

1. Income Allocation (/income-allocation)

• •Input salary amount received into primary account (VCB)
• •Auto-calculate fund amounts based on configured percentages
• •Generate a transfer to-do list (e.g., "Transfer 5M from VCB → MB Bank")
• •Mark transfers as "Done" → update physical account balances

2. Expense Management (/expenses)

• •Each Fund maps to a default PhysicalAccount (e.g., Ăn uống → VCB)
• •Log expense by selecting a Fund → system deducts from the linked PhysicalAccount
• •Alert if a Fund is exhausted but the PhysicalAccount still has balance (cross-fund overspend)

3. Investment Journal (/investments)

• •Log stock purchases: date, ticker, quantity, matched price
• •No sell feature in v1.0
• •End-of-month review (24th): input current market price for held tickers
• •Investment notes: strategy reasoning per asset ("Why did I buy this?", "Next month plan?")

4. Reporting (/reports)

• •Cycle Report: spending summary for 25/N → 24/N+1
• •Budget vs Actual: horizontal bar chart data — % spent per fund
• •Portfolio Growth: column chart data — principal vs market value over time

User Flow

1. •Day 25 — Receive salary → app splits by % → user transfers real money per suggestions → tick "Done"
2. •Daily — Log expense → pick Fund → app deducts from linked bank account
3. •Stock purchase — Log qty/price → app deducts from Investment fund & MB Bank
4. •Day 24 — Input current stock prices → view monthly report → write strategy notes

Database Design

Prisma schema at prisma/schema.prisma. Key relationships:

• •Fund.defaultAccountId → PhysicalAccount.id (each fund maps to a bank account)
• •Transaction.fundId → Fund.id
• •Transaction.accountId → PhysicalAccount.id
• •Transaction.fiscalCycleId → FiscalCycle.id
• •InvestmentTransaction.assetId → InvestmentAsset.id
• •InvestmentSnapshot.assetId → InvestmentAsset.id

Use Decimal @db.Decimal(15, 2) for all monetary fields.

NestJS Module Structure

src/
├── main.ts
├── app.module.ts
├── prisma/
│   ├── prisma.module.ts        # Global PrismaModule
│   └── prisma.service.ts       # PrismaClient wrapper
├── accounts/
│   ├── accounts.module.ts
│   ├── accounts.controller.ts
│   ├── accounts.service.ts
│   └── dto/
├── funds/
│   ├── funds.module.ts
│   ├── funds.controller.ts
│   ├── funds.service.ts
│   └── dto/
├── income-allocation/
│   ├── income-allocation.module.ts
│   ├── income-allocation.controller.ts
│   ├── income-allocation.service.ts
│   └── dto/
├── expenses/
│   ├── expenses.module.ts
│   ├── expenses.controller.ts
│   ├── expenses.service.ts
│   └── dto/
├── investments/
│   ├── investments.module.ts
│   ├── investments.controller.ts
│   ├── investments.service.ts
│   └── dto/
├── fiscal-cycles/
│   ├── fiscal-cycles.module.ts
│   ├── fiscal-cycles.controller.ts
│   ├── fiscal-cycles.service.ts
│   └── dto/
└── reports/
    ├── reports.module.ts
    ├── reports.controller.ts
    └── reports.service.ts

Conventions

• •Validation: Use class-validator + class-transformer with DTOs
• •API prefix: /api/v1 (set in main.ts)
• •Error handling: NestJS built-in exception filters
• •Naming: kebab-case for routes, camelCase for TS, PascalCase for classes/models
• •Single-user app: No auth required in v1.0 (personal use only)

Build Order (Suggested)

1. •Prisma schema (add missing relations & fields) + PrismaModule
2. •Accounts CRUD
3. •Funds CRUD
4. •FiscalCycle management
5. •Income Allocation (salary input + auto-split + transfer to-do)
6. •Expense Management (logging + alerts)
7. •Investment Journal (purchase log + snapshots + notes)
8. •Reporting (cycle summary + budget vs actual + portfolio growth)

UI Direction (for future frontend)

• •Primary: Green (investment), Secondary: Blue (banking), Accent: Orange (spending alerts)
• •Main screen: progress bars per fund showing spend velocity