What “processed in your browser” means
Separate local file processing from page requests, storage, and tools that inherently need the network.
ToolMellow ·
The file operation happens on your device
For ToolMellow’s current local tools, the application receives the file you choose through the browser’s file picker. Its processing engine reads those bytes locally and returns a downloadable result. A remote conversion job is not involved.
A page still has to load
Your browser requests the page, scripts, fonts, and engines from the hosting service. Those requests reveal network information such as your IP address. Local processing means your selected file content is not uploaded; it does not mean the website can load without any network request.
A worker keeps the interface responsive
Large tasks are placed in a Web Worker so the main page can show progress and respond to Cancel. This is a responsiveness mechanism, not a security boundary against other scripts from the same site. That is why the processing pages avoid third-party advertising and session replay.
Temporary means temporary
Input and results are held in memory. Explicit workflow buttons transfer selected results between tools in the same tab. Refreshing or closing the tab can discard that work. Save a result before leaving if you want to keep it.
Network diagnostics are a different kind of task
A real speed test exchanges traffic with an endpoint. IP observation and DNS comparison also make server requests. ToolMellow discloses those requests before use: DNS sends the entered name to selected providers, and speed tests transfer synthetic bytes only after Start. File and text tools continue to process their inputs locally.