A ready-to-use, MIT-licensed SaaS application boilerplate combining Flask (Python) backend, PostgreSQL database and a ReactJS frontend. It provides user authentication (JWT + cookie tokens), modular project structure, demo components, DB scaffolding and deployment-friendly scripts so developers can quickly prototype and build production-ready SaaS applications.

Open-Source SaaS Boilerplate (Python / PostgreSQL / React)

A free starter for building a SaaS web application. This boilerplate combines a Flask backend, PostgreSQL database, and a React frontend to help you bootstrap a scalable SaaS product quickly.

• Tech stack: Python (Flask) backend, PostgreSQL database, ReactJS frontend, Webpack for building, and SCSS for styling.
• Goal: deliver a working, modular SaaS app architecture with authentication, API endpoints, and a responsive UI out of the box.

Why this boilerplate helps

• Jumpstart your SaaS project with a proven structure, so you can focus on domain logic rather than boilerplate.
• Frontend and backend are organized side-by-side in cohesive modules, making development and maintenance easier.
• Built-in UI patterns and components speed up the creation of dashboards, user management, and critical SaaS workflows.

Core architecture

• Backend
• Flask-based with blueprints to keep features decoupled.
• JWT-based authentication with server-side API support.
• Automatic API/module import: add a new API component and it’s registered automatically.

• Essential server-side API endpoints for authentication and profile management.

• Frontend

• React SPA with routes for register, login, finish registration, and confirmation flow.
• Responsive, mobile-friendly design with a dynamic left menu and header dropdowns.
• Lazy-loaded components to improve performance.

• A single source of truth for routes and components, reducing boilerplate.

• Data and models

• Core tables include User, Role, Account, and AccountHistory.

• Role-based access and user management built in to support common SaaS use cases.

• UI and UX

• Alerts, dropdown menus, and other UI blocks are componentized and customizable.
• Left navigation and top menus are driven by JSON-based data structures for flexibility.
• All styles live in one folder for fast theming and Theme swaps.

Key features

• User authentication
• Email verification and standard registration/login/logout flows.
• Session management via JWT with secure cookie handling.

• Optional finish-registration flow and automatic redirects where appropriate.

• API and modularity

• Backend and frontend features are split into modules (“blueprints”) that can be developed and tested independently.

• Automatic API import and simple extension points for adding new functionality.

• Front-end capabilities

• SPA routing with a responsive design.
• Lazy loading for performance optimization.
• JSON-driven navigation menus with optional icons and colors.

• Reusable UI components (alerts, forms, profile views, etc.).

• Error handling and reliability

• Graceful 404 and basic error pages to guide users when routes are missing.

• Consistent error handling patterns across server and client.

• Theming and customization

• All styles centralized to enable quick theme changes.
• Global aliases and ES6 features for modern JavaScript syntax.

• A single framework for adding new components and features without breaking existing code.

• Deployment and development convenience

• Docker/Docker-Compose ready for local and cloud deployments.
• AWS Beanstalk-friendly structure.
• Clear guidelines for environment variables and configuration.