Where your document goes when you edit online

"Online editor" covers a few different things, and they handle your file differently. None of this is hidden; it's how these services are designed to work.

  • Cloud office suites. Google Docs edits a .docx after you upload it to Google Drive, and Microsoft's free web version of Word works with files saved in OneDrive. Your document is stored in your account on their servers, under their terms and your account's sharing settings. For many people that is exactly what they want: sync, sharing and real-time co-editing.
  • Free converter and editor websites. Most send the file to their server, process it there and send a result back. How long they keep it, and who can access it in the meantime, depends on each site's policy, which you have to take on trust.
  • Browser-based editors that run locally. The editing software is downloaded into the page, and your file is read from your disk into that page. Nothing needs to be sent anywhere for the editing to work.

The question to ask of any tool is simple: does my file need to leave my computer for this to work? For editing a document, the honest answer is no.

What a .docx file actually is

A .docx is a ZIP archive of XML files, defined by an open standard, ECMA-376 (Office Open XML), also published as ISO/IEC 29500. Inside are the document text with its formatting, the styles, numbering definitions for lists, images, and settings such as page size and margins. Because the format is documented, many programs can read and write it, including free desktop suites and browser-based tools.

It also explains why every editor other than the one that created a file shows it slightly differently: the standard is large, and each program supports the parts it needs.

Editing in the browser, without an upload

Vault Studio Pro Docs works like this:

  1. When you open a .docx, your browser reads the file from your disk into the page's memory, using the same file picker as any upload form. The difference is that the page keeps the file instead of sending it.
  2. An open-source library, mammoth.js, converts the document's XML into an editable web document. Docs then restores details that mammoth leaves out, such as table borders, cell shading, column widths and page borders.
  3. You edit the document in the page, with the toolbar and the usual keyboard shortcuts.
  4. When you save, another open-source library, docx, builds a new .docx file from the edited document, and your browser downloads it to your computer.

Every page of the app is served with a Content-Security-Policy that stops it from connecting to any other website, so even a bug couldn't quietly send your document to a third party. Our guide to what "client-side" really means shows how to check that for yourself.

How to edit a .docx in Vault Studio Pro

  1. Go to Docs in the app, then open your .docx or drag it onto the window.
  2. Edit the text. The toolbar covers fonts and sizes, bold, italic, underline, colour and highlight, headings, lists and checklists, tables, alignment, line spacing, links and images. Find and replace is on Ctrl+F (Cmd+F on a Mac).
  3. If you are reviewing, use comments and suggestion mode, then accept or reject each change before you export.
  4. Press Ctrl+S (Cmd+S) to save a .docx copy, or use the export menu for other formats.
  5. Open the saved file once in the program your recipient uses, if the layout matters.

While you work, a draft is autosaved in your browser's storage on this device, so a refresh doesn't lose your changes. Pro adds revision history & rollback: snapshots you can go back to. See pricing for the plans.

What survives the round trip, and what does not

"Round trip" means opening a .docx, editing it and saving it again. Here is what to expect, based on what the import and export code handles.

Kept

  • Paragraphs, headings (as real Word heading levels), quotes, code blocks and page breaks.
  • Bold, italic, underline, strikethrough, superscript, subscript, text colour, highlight, font and size.
  • Bulleted and numbered lists, including nested lists, with numbering restarting where it should.
  • Tables, including merged cells, borders and cell shading.
  • Links, as clickable hyperlinks, and images, scaled to fit the page width.
  • Paragraph alignment.

Simplified or dropped

  • Headers and footers, text boxes and floating shapes from the original may be simplified or left out when the file is opened.
  • Tracked changes and comments made in another program may not come through. Accept or reject them in that program first if you need a clean copy.
  • Comments and suggestions added in Docs are for your review inside the app. Resolve them before exporting; don't expect them to appear as comments in the saved .docx.
  • Page setup. The saved .docx uses standard page settings, so custom margins, columns, page borders and watermarks you set in Docs aren't written into the file.
  • Exact fonts. A .docx names its fonts but usually doesn't contain them. The computer that opens it substitutes any font it doesn't have.
  • Macros, mail merge and fields such as automatic cross-references aren't supported.

One more detail, since this guide is about privacy: the saved .docx records the document title and names "Vault Studio Pro" as the creating application in its file properties. It doesn't add your name.

If a document depends on a complex layout, keep the original and use Docs for text edits, reviews and redlines on a copy.

Starting from a .doc, Google Docs or Pages file

Docs opens .docx files. If you have something else, convert it to .docx first:

  • An older .doc file: the binary format used before .docx. Open it in LibreOffice Writer or another word processor and save it as .docx.
  • A Google Doc: in Google Docs, use File, then Download, then Microsoft Word (.docx). The download is a normal file on your computer, which you can then open in Docs.
  • A Pages document: in Pages, use File, then Export To, then Word.
  • A PDF you need to rewrite: the PDF editor can convert a PDF into an editable .docx. Scanned pages need OCR first, which our OCR guide explains.

Converting a document you already keep in a cloud service doesn't un-upload it, of course. The point is for the next edits, and the next document, to stay on your machine.

Exporting: .docx, PDF and Markdown

  • .docx is the right choice for anything someone else will edit.
  • PDF export is an image of each page. It looks right, but the text in it can't be selected or searched. For a PDF with real text, export the .docx and use your system's print to PDF, or use the print option in Docs.
  • Markdown gives you plain text with headings, lists and links, useful for notes, wikis and code repositories.

Privacy notes worth knowing

  • Browser storage is not encrypted. Autosaved drafts live in your browser profile on this device. On a shared computer, export your file and delete the project when you are done.
  • Dictation is the exception to "on your device". It uses your browser's speech recognition, which in Chrome sends audio to Google and in Safari to Apple. The app asks before it starts.
  • Sending the file is still sending the file. If the finished document is sensitive, put it in a password-protected .vault with the File Safe before emailing it. Our encryption guide covers how to share the password safely.

Try it

Docs is free and needs no account. Open a .docx in the app, or read more on the .docx editor page. If your work also involves spreadsheets, the .xlsx editor works the same way.

Open DocsSee plans and pricing

Sources

  1. Work with Microsoft Office files. Google Docs Editors Help
  2. Free Microsoft 365 Online: Word, Excel, PowerPoint. Microsoft
  3. ECMA-376: Office Open XML File Formats. Ecma International
  4. mammoth.js: convert .docx documents to HTML. open-source project on GitHub
  5. docx: generate .docx files with JavaScript. open-source project on GitHub