Building a software-as-a-service (SaaS) application requires selecting the right mix of programming libraries and frameworks to help accelerate development. Choosing libraries with robust functionality, strong community support, and easy integration can make developing, deploying, and scaling a SaaS much simpler. Here are some of the most popular libraries software engineers use when building SaaS applications.
Django is a high-level Python web framework that encourages rapid development and clean code. As a batteries-included framework, Django comes with an object-relational mapper, templating engine, admin interface, user authentication tools and more out of the box. Django helps developers avoid recreating common web development needs so they can focus on their SaaS’s core functionality. With its many third party libraries and over decade of community knowledge, Django powers SaaS applications like Discourse, Sentry, and Zapier.
Flask is a lightweight Python web application framework. With its barebones approach, Flask provides developers flexibility and scalability. Developers can select only the extensions and tools they absolutely need without unnecessary bloat. Unlike Django, Flask does not come with batteries included. This allows developers to have fine-grained control over component choices like using SQLAlchemy for the ORM or Jinja for templating. The simplicity and customizability of Flask make it easy to use for both simple and complex web applications like Pinterest, Twilio, and Zapier.
Ruby on Rails
Ruby on Rails is an MVC framework providing structure and conventions optimized for programmer happiness and sustainable productivity. As one of the first widely popular web app frameworks, Ruby on Rails has a strong community and ecosystem of libraries. Rails uses the Ruby language which prioritizes developer experience with an expressive syntax. Rails makes building CRUD apps fast with code generation capabilities for models, views and controllers. Basecamp, Shopify, Airbnb, and GitHub are popular SaaS apps built using Ruby on Rails.
Laravel is a full-stack, open source PHP framework with expressive, elegant syntax that accelerates building modern web apps. Laravel comes baked in with robust tools like a modular packaging system with auto-loading, migrations, an IoC container, unit testing, queues and more. Laravel’s SOLID design patterns and developer focused UX makes it easy to use and customize. Laravel powers popular SaaS apps like Cachet, Envoy, and Booking.com. The Laravel community releases frequent updates aligned with latest PHP standards and security best practices.
Spring Boot is an open-source Java framework that helps developers rapidly build production-ready web and backend applications. It comes with an embedded HTTP server, so no need to deploy WAR files to external servers. With dependency injection built-in, Spring Boot has immense community support and integrates easily with databases, messaging queues, caching servers, and more. Companies like Netflix, Shopify, and Airbnb use Spring Boot to quickly build, test, and deploy their services.
ASP.NET Core is a Microsoft web framework for building web and cloud applications using .NET and C#. It provides a “batteries-included” development experience with routing, dependency injection, authentication, configuration, and more built-in. ASP.NET Core was rebuilt from the ground up to be cloud-ready. It enables modern application architectures using containers and microservices. Companies like Microsoft, Honeywell and Epic Games use ASP.NET Core for its security, performance, and Visual Studio integration.
NestJS is a server-side TypeScript framework heavily inspired by Angular. It uses express under the hood but abstracts away much direct interaction with express itself. NestJS enables modular, testable and scalable backend applications thanks to TypeScript’s strong typing. With an architecture organized around modules, controllers and providers, NestJS encourages writing reusable, loosely coupled components. Companies like TerminusDB and Adapty use NestJS to merge object-oriented programming patterns with Node.js for building robust backends.
Selecting languages and frameworks is an integral part of SaaS architecture. The libraries discussed here are proven tools for rapidly delivering the right APIs, integrations, UI, caching, security, and all the components expected in a modern SaaS application. While there is no single right choice, Django, React, Flask, Rails, Laravel and Vue are very capable tools. Thoroughly evaluate technical requirements, internal skills, and product goals when deciding which libraries make the most sense for building your SaaS.