Historically, complex operations like image manipulation or heavy data processing had to be done on a server. You'd send your data, wait for the server to process it, and then download the result.
WebAssembly and Native Performance
With technologies like WebAssembly (WASM), we can now run code written in languages like C, C++, and Rust directly in the browser at near-native speeds.
Coupled with modern web APIs like the File System Access API, we can now build applications that feel and perform like native desktop apps, entirely within the browser.