Build unlimited SaaS apps, mobile apps, and websites for free using VS Code, Roo Code, and Gemini API—no subscriptions or coding required.

The digital landscape is flooded with tools that promise the ability to create websites and complex applications using AI and no-code methods. Platforms like Lovable, Replit, and Cursor have captured attention, but they all share a critical limitation: they are primarily paid services. You start a project, get invested, but quickly run into a subscription wall that stops your progress.

You don't need to pay for these expensive subscriptions to bring your ideas to life. This article details a method that is 100% free, allowing you to build unlimited no-code SaaS apps, mobile applications, and websites without writing a single line of code.

This process eliminates credit limits and hidden costs, granting you a powerful development setup that uses free, industry-leading AI models. By following the complete installation guide below, you will have a ready-to-use, free environment where you can use natural language prompts to build professional software.

The Essential Toolkit: A Free and Unlimited Development Environment

To realize your vision of creating a SaaS app or website, we need to integrate two powerful, free components: a professional code editor and a free AI coding extension. This combination bypasses the need for proprietary, paid platforms.

Step 1: Download and Install Visual Studio Code (VS Code)

The foundation of our free setup is a professional-grade code editor. We will use Visual Studio Code (VS Code), which is the industry standard and completely free to use.

1. Open your browser and search for VS Code.
2. Download and install the appropriate version for your operating system (Mac OS or Windows).
3. Open VS Code. You will see a clean dashboard where you can create new folders or open existing projects. This free software is where the underlying code for your website or app will be generated and stored.

Step 2: Integrate AI with the Roo Code Extension

Now, we must connect the AI to VS Code, enabling you to write prompts instead of code. This is done using a specialized extension.

1. In the VS Code dashboard, click the Extensions button (usually on the side menu).
2. Search for Roo Code.
3. Click the first result and install it. You may need to grant permission to trust the publisher.

Roo Code functions as your personal AI co-pilot. It handles the complex task of translating your natural language instructions into functional code directly within the editor, similar to how paid AI assistants work.

Step 3: Configure Your Project and Free Gemini API

With the tools installed, we need to create a project directory and connect it to a free, powerful AI model.

1. Create a Project Folder: In VS Code, click Open Folder and create a new directory on your computer, such as "Test SaaS." All your software files will be saved here.
2. Access Roo Code: Click the Roo Code icon (it may appear as a small symbol or within the sidebar). A configuration panel will appear, asking you for API details.

Crucial: Using the Free Gemini API

Most people assume all AI APIs are paid, but Google’s Gemini API is free and offers a substantial credit limit for development purposes. This free allowance is sufficient for prototyping and building numerous applications. Furthermore, the daily credit limit refreshes, and if you ever hit the ceiling, you can simply generate a new API key using another Google account.

1. Choose the Model: In the Roo Code panel, select Gemini as your AI model.
2. Generate Your API Key: Go to your browser and search for Google AI Studio.
3. On the Google AI Studio site, navigate to Get API Key and create a new key.
4. Copy this key and paste it into the API Key field in the Roo Code panel.
5. Select the Model: Choose Gemini 2.5 Pro, as it offers the best performance for coding tasks.

Click Let's Go. Grant the necessary permissions to VS Code. Once complete, your Roo Code setup is ready to build your apps.

The Conversational Workflow: Building Unlimited Applications

With your free, powerful environment set up, you can now build without the fear of subscription costs.

Setting Up the Foundation: A Next.js Template

Modern SaaS products are often built on frameworks like Next.js. To start with a strong foundation, you can prompt the AI to create the boilerplate:

Setup a boilerplate template for a SaaS product in Next.js.

1. The AI Executes: The AI will execute the necessary commands in the terminal.
2. Files Appear: You will see the foundational files for your application begin to populate the file sidebar. The AI automatically installs necessary dependencies, saving you from complex manual setup.

Debugging and Handling Errors

Since this is a free and open setup, you may encounter more errors than you would with a highly refined, paid tool like Lovable. This is a crucial part of the learning process.

• API Limits: If you receive an error about too many requests or exceeding your quota, simply generate a new Gemini API key and replace the old one in the Roo Code settings.
• Error Loops: Sometimes the AI gets stuck trying to fix the same error repeatedly. If this happens, you can use other free resources like ChatGPT to get suggestions on how to resolve the error. Ultimately, you will then submit a refined prompt to Roo Code to implement the fix. You can learn to solve complex issues by providing the AI with clear instructions based on the error messages.

Previewing Your Work Locally

Once the foundational files are set up, you can view your work-in-progress:

1. In the Roo Code prompt box, ask: I want to see how my SaaS looks.
2. The AI will run a command to host the application locally and provide you with a URL, typically localhost:3000.
3. Open this URL in your browser.

You now have a live, interactive preview of your application. As you continue to give prompts and make changes, they will be reflected instantly in your local browser, providing a development experience that mirrors the expensive, paid tools.

Benefits of the Free Setup: Unlimited Power and Opportunity

This free methodology offers significant advantages over subscription-based models:

Unrestricted and Cost-Free Development

By eliminating the need for paid APIs and proprietary software, you gain unlimited creation potential. You can prototype as many SaaS products, websites, and mobile apps as you want without worrying about monthly fees or exhausting your credits. This freedom is essential for iterative learning and rapid product development.

Learning the Core Fundamentals

Working within VS Code provides exposure to a professional code editing environment. Even without writing code, you gain an understanding of file structures, dependencies, and the overall development process. This knowledge is invaluable and positions you ahead of those who rely solely on closed, proprietary no-code platforms.

Building Scalable, Professional Software

Your applications are built using modern frameworks like Next.js, meaning the software you create is professional, scalable, and ready for future expansion. You are not building on proprietary platforms that lock you in; you are building on open-source standards that ensure your project's longevity.

Conclusion: Seize Your Opportunity to Build

The power to create professional-grade SaaS apps, mobile apps, and websites is no longer defined by your bank account. By leveraging the free tools—VS Code, the Roo Code extension, and the Google Gemini API—you have established a robust, cost-free development environment that rivals the most expensive options on the market.

This is your opportunity to build unlimited applications, refine your ideas, and enter the digital creation space without financial limitations. Now that your free, powerful toolkit is ready, you can begin submitting your prompts and transforming your ideas into deployable, functional software. The only remaining cost is your time and imagination.