Quick answer: prefer a local browser workflow when the task does not genuinely require a server, and always verify important output.
Why DOCX can be processed in a browser
A modern .docx file is a ZIP package containing XML, relationships and embedded media. A browser library can unpack those parts, read the document structure and create a safe HTML or text representation without Microsoft Word.
This is useful for quick inspection, content reuse and recovery of embedded images. It does not reproduce the complete Word layout engine.
Choose the output that matches the job
Use the reader when you only need to inspect the document. Convert to HTML for a portable web representation, convert to Markdown for simpler structured text, or extract images when the media assets are the goal.
Tables, lists and headings usually transfer more predictably than floating shapes, text boxes, tracked changes, macros or highly designed page layouts.
Review formatting and hidden material
Compare the converted result with the original before publishing it. A conversion may omit comments, revision history, headers, footers, page breaks or fields that depend on Word.
Do not assume that converting a document removes every sensitive detail. Inspect the result and use appropriate metadata-cleaning workflows when privacy requirements are strict.
Know which files are supported
These tools support modern .docx files. The older binary .doc format is different and is not parsed by the local DOCX runtime. Open a legacy file in a trusted office application and save a copy as .docx first.
Corrupted, encrypted or extremely large documents may not open reliably in a browser tab. Keep originals and use desktop software for archival or legally significant conversions.