Inventory SaaS

An offline-first, multi-tenant SaaS Inventory Management System built with Fastify, Next.js 14, and Drizzle ORM.

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Architecture Overview

inventory-saas/              ← Turborepo monorepo root
├── apps/
│   ├── api/                 ← Fastify v5 REST API (Node.js)
│   └── web/                 ← Next.js 14 App Router frontend
└── packages/
    └── shared/              ← Shared Zod schemas, types & constants

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Tech Stack

Layer	Technology
Monorepo	pnpm workspaces + Turborepo
Backend	Fastify v5, Drizzle ORM, PostgreSQL 15
Authentication	JWT (jose), bcryptjs, HTTP-only cookies
Frontend	Next.js 14 (App Router), React 18, TanStack Query
Offline sync	Dexie.js (IndexedDB), custom sync engine
State management	Zustand
Styling	Tailwind CSS
Validation	Zod (shared schemas across API & web)
Language	TypeScript (strict)
Testing	Vitest (unit), Playwright (e2e)
CI/CD	GitHub Actions

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Features

• Offline-first — all reads/writes go to local IndexedDB; background sync pushes/pulls changes when online
• Multi-tenancy — each tenant is fully isolated via Row-Level Security (RLS) enforced in the API
• RBAC — role-based access control (admin / manager / staff) enforced at route level
• Sync engine — vector-clock-based conflict detection and resolution
• Conflict resolution — last-write-wins with conflict log for manual review
• JWT auth — short-lived access tokens (15 min) with silent refresh via refresh tokens

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Prerequisites

Tool	Version
Node.js	20+
pnpm	9+
PostgreSQL	15+

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Getting Started

1. Clone the repository

git clone https://github.com/Anish-1205/inventory-saas.git
cd inventory-saas

2. Install dependencies

pnpm install

3. Configure environment variables

API (apps/api):

cp apps/api/.env.example apps/api/.env
# Edit apps/api/.env — set DATABASE_URL, JWT_SECRET, COOKIE_SECRET, etc.

Web (apps/web):

cp apps/web/.env.local.example apps/web/.env.local
# NEXT_PUBLIC_API_URL=http://localhost:3001/api/v1

4. Run database migrations

pnpm db:migrate

5. Start development servers

pnpm dev

This starts both the API (port 3001) and the web app (port 3000) in parallel via Turborepo.

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Available Scripts

Script	Description
pnpm dev	Start all apps in watch/dev mode
pnpm build	Build all packages and apps
pnpm test	Run unit tests across all workspaces
pnpm lint	Run ESLint across all workspaces
pnpm db:migrate	Apply pending Drizzle migrations (API only)
pnpm db:generate	Generate Drizzle migration files from schema changes

Per-app scripts

# API
pnpm --filter @inventory-saas/api test:coverage   # unit tests with coverage
pnpm --filter @inventory-saas/api dev             # API only

# Web
pnpm --filter @inventory-saas/web test            # unit tests
pnpm --filter @inventory-saas/web test:e2e        # Playwright e2e tests
pnpm --filter @inventory-saas/web dev             # web only

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API Endpoints Overview

All endpoints are prefixed with /api/v1.

Method	Path	Auth	Description
POST	/auth/register	✗	Register a new tenant + admin user
POST	/auth/login	✗	Login and receive JWT tokens
POST	/auth/refresh	✗	Refresh access token
POST	/auth/logout	✓	Revoke refresh token
GET	/auth/me	✓	Get current user profile
GET	/users	✓ admin/manager	List users in tenant
POST	/categories	✓ admin/manager	Create category
GET	/categories	✓	List categories
POST	/products	✓ admin/manager	Create product
GET	/products	✓	List products (paginated)
GET	/products/:id	✓	Get single product
PATCH	/products/:id	✓ admin/manager	Update product
DELETE	/products/:id	✓ admin	Delete product
GET	/inventory	✓	List inventory levels
POST	/inventory/:productId/adjust	✓	Adjust stock
POST	/sync/push	✓	Push local outbox to server
GET	/sync/pull	✓	Pull server changes since seq
GET	/sync/state	✓	Get current server sequence

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Project Structure

inventory-saas/
├── apps/
│   ├── api/
│   │   └── src/
│   │       ├── config/          # Zod-validated env, DB connection
│   │       ├── db/
│   │       │   ├── migrations/  # Drizzle SQL migrations
│   │       │   └── schema/      # Drizzle table definitions
│   │       ├── lib/             # errors, pagination, logger helpers
│   │       ├── modules/         # Feature modules (auth, products, …)
│   │       ├── plugins/         # Fastify plugins (auth, rbac, tenant)
│   │       └── server.ts        # App entry point
│   └── web/
│       └── src/
│           ├── app/             # Next.js App Router pages & layouts
│           ├── components/      # Reusable React components
│           ├── lib/
│           │   ├── api/         # Axios client + TanStack Query hooks
│           │   ├── auth/        # Token manager
│           │   ├── db/          # Dexie IndexedDB schema
│           │   └── sync/        # Sync engine & network monitor
│           ├── store/           # Zustand stores
│           └── test/            # Vitest setup files
└── packages/
    └── shared/
        └── src/
            ├── constants/       # Role & sync status enums
            ├── schemas/         # Shared Zod schemas
            └── types/           # Shared TypeScript types

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Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feat/my-feature)
3. Commit your changes using Conventional Commits
4. Push to your branch and open a pull request
5. Ensure CI passes (lint + type-check + tests)

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License

MIT