How I Built Browser-Based Tools Without Sending User Data to a Server

When building small online utilities, one question comes up surprisingly often: Does the user's data really need to leave their browser? For many types of tools, the answer is no. That's one of the principles behind Giga Useful Tools: whenever possible, tools should perform their processing directly in the browser instead of uploading user data to a backend server. Why process data in the browser? A traditional web application might work like this: User ↓ Upload data ↓ Server ↓ Process data ↓ Send result back ↓ User For many simple utilities, this architecture is unnecessary. If a user wants to convert an image, generate a QR code, encode some text, or perform a calculation, there may be no reason to send that information anywhere. A browser-based approach looks more like this: User ↓ Browser ↓ Process locally ↓ Result The server only needs to deliver the application itself. A simple example Imagine an image conversion tool. A server-base