Comparison
Document Previewer vs Foretaste
Both are Firefox add-ons that open a document link without saving it first. Document Previewer uses the preview feature of Google Docs, by its own description; Foretaste reads the file inside your own browser tab.
Everything said about Document Previewer here is in its own words, from its own listing or policy, read on 13 October 2026. Sources
01
Side by side
| What | Document Previewer | Foretaste |
|---|---|---|
| How a document is opened | “This add-on uses the preview feature of Google docs to preview documents (doc, docx, ppt, pptx, xls, xlsx, pdf) online,” S1 The same summary goes on to say this happens without downloading the file first. | Fetched from the site it is on and read inside your browser. Foretaste also offers Google’s viewer, but only after it has failed itself, behind a warning and a confirmation. |
| Who the file is shared with | “Any file previewed using this add-on will be made accessible to Google.” S1 The add-on says this itself, under “WARNING: This add-on uses the preview feature of Google docs.” | Only the site the file is already on. No file, file name or address reaches a Foretaste server. |
| The gesture | “Opening any link to a doc, docx, ppt, pptx, xls, xlxs or pdf file will open a page giving the user the option” S2 Quoted as written. The sentence goes on to offer previewing the file or downloading it directly. | A button beside each file link opens a card showing what the page already said about the file, and the card fetches nothing. Press Open and the file is read in a panel over the page, or in a tab. Right-click works too. |
| What it opens | doc, docx, ppt, pptx, xls, xlsx and pdf, as listed in its summary. S1 | Draws DOCX, XLSX, XLS, PPTX and PDF, plus OpenDocument, CSV, text and code, pictures, audio, video, subtitles, fonts, databases, calendars and contacts. |
| Archives | None among the formats its listing names. S1 | ZIP, 7z, RAR, TAR and more, with the files inside them opened in the same tab. A remote ZIP is listed from its index: about 67 KB read of a 40 MB archive. |
| Last updated | 18 December 2022 (version 2.0). S1 | October 2026 (version 1.6.0). |
02
Foretaste, reading a Word document
The real viewer, running on this page. Nothing is installed and nothing is uploaded: scroll it, press things.
The real Foretaste viewer reading sample.docx on a measured Letter page, running on this page.
Word document1.2 KBWords 30
- Tables
- 1
- Page
- Letter
- Type
- application/vnd.openxmlformats-officedocument.wordprocessingml.document
The whole file was read - 1.2 KB.
How this was read
- Asked how big it is—
- Asked for the whole file1.2 KB
Processed locally · Foretaste reads files on your device and does not upload them.
External viewer · Google fetches the file themselves.
What the site said about this file
- Name
- sample.docx
- Kind
- Word document
- Reported type
- application/vnd.openxmlformats-officedocument.wordprocessingml.document
- Size
- 1.2 KB
- Partial reads
- Supported. Foretaste can read part of the file without fetching all of it.
- Address
- http://localhost:8797/sample.docx
Reads the whole file to compare against a published checksum. Nothing is sent anywhere.
The questions people ask
Is Foretaste an alternative to Document Previewer?
Yes, on Firefox: both open a document link without saving it first. Document Previewer uses the preview feature of Google Docs, by its own description, and Foretaste reads the file in your browser. Foretaste also opens archives, data files and media, and shows how much of each file it read.
Does Document Previewer send files to Google?
Its own listing warns: “Any file previewed using this add-on will be made accessible to Google.” What Google does with a file is described in Google’s own policy, not here.
Does Foretaste work on Firefox for Android?
Yes. Foretaste runs on Chrome, Edge and Firefox, including Firefox for Android.
Sources
Where each claim comes from
Read on 13 October 2026, and checked again by 13 April 2027. If a source has changed by then, this page changes with it.