Understand what local browser conversion means and when a backend service might still be needed.
Local means device-side
Supported conversions run in the browser tab, so files do not need to be uploaded to this local development server for processing.
Some engines load code
Libraries such as PDF tools or media engines can load in the browser, but the selected file is still handled locally when supported.
Backend cases
OCR, large media jobs, exact Office rendering, and rare formats may need a protected backend in production.