A few years ago, almost every "online tool" worked the same way: you upload your file to a server, wait for a response, then download the result. Simple, but it has real costs — server bandwidth, storage, latency, and (the big one) your file leaves your device.
Lately more tools are shifting that entire pipeline into the browser itself. No upload, no server round-trip, no storage. Here's why that shift is happening, and what it actually takes to build a tool this way.
Why client-side processing makes sense
Privacy by default. If a file never leaves the browser, there's nothing to log, nothing to breach, nothing to accidentally retain. For anything image or document related, this matters more than most devs give it credit for.
Cost. Every file processed server-side costs compute and bandwidth. Processed client-side, it costs the user's device — which for most modern browsers is more than capable.
