Before you download
How to view a file without downloading it
Foretaste is a free browser extension that reads a file from its link and shows you what is inside, in your browser, without downloading it. Right-click, look, and decide afterwards — on Chrome, Edge and Firefox, with nothing uploaded anywhere.
The alternative is the one you already know. A link called
attachment?id=18392. A 300 MB archive that might hold this year's slides or
last year's. You cannot tell from the outside, so you download it, wait, find out, and now
it is in your downloads folder whether you wanted it or not.
01
What you get, by kind of file
Right-click the link, choose Open with Foretaste, and the browser fetches the file from the site it already lives on and reads it in the tab. What appears depends on what it turns out to be:
- Archives. A folder tree of everything inside, with sizes, read from the index at the end of the file rather than from the whole archive. See how to open a ZIP without downloading it.
- Documents. Headings, tables and images from a Word file, a PDF or an OpenDocument — and a Word document is laid out on real pages, measured from the sheet size and margins it declares. Read how to preview Word, Excel and PowerPoint documents.
- Spreadsheets and tables. Every sheet as a tab, cell values in a scrollable grid, and a CSV of any size turned 200 rows at a time.
- Databases. Every table, its columns and its CREATE statement, out of the first 256 KB. See how to preview SQLite database schemas from a link.
- Datasets. Row count, row groups and column types out of a Parquet footer, with no data page read at all. See how to inspect Parquet metadata without downloading.
- Text, code and logs. Syntax highlighted, Markdown rendered, JSON as a tree, and a log filtered to the levels you want. This is also the kind most likely to download instead of opening when you click it — see how to open links that download instead of opening.
- Media. Images with their dimensions and Exif, and audio and video streamed from the original address, so only the part you play is fetched.
- Invitations and contact cards. Every event in an
.ics, with the times in your own locale, and the fields on a.vcf— without either one reaching a calendar or an address book.
02
Three steps, once
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Your browser asks for website access, once.
It is granted at install and there is no second prompt, because the file behind a link is routinely served from a different address than the page it was linked on. Saving a file to disk needs none of it, which is what keeps that part never gated. What that access does and does not buy.
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Right-click a file link and choose "Open with Foretaste".
The file opens in a panel over the page. Read it, then save it or close it and carry on.
03
When a file is not what it says it is
Foretaste is not antivirus software and does not pretend to be. It cannot tell you whether a file is dangerous, and nothing on this page should be read as saying it can.
What it can do is read the file's first kilobyte and check it against the signatures real
formats begin with. Names lie and servers mislabel things constantly; the leading bytes do
not. If a file called report.pdf begins like an executable, Foretaste says the
name and the contents disagree, and says which one it believes.
04
Your files never reach us
Foretaste requests the file from the website it already lives on, the same request your browser would make if you clicked the link, and reads it in the tab. No file, no file name and no page address is sent to a Foretaste server, because there is no Foretaste server for a file to go to.
There is no analytics, no telemetry and no crash reporting either, and a check in the build script fails the release if a hardcoded address outside a short allowlist appears in the output.
05
Why not an online viewer
Because an online viewer needs the file on its own server first, which means downloading it and then uploading it. The whole saving disappears, and a confidential document has been somewhere neither you nor the sender chose.
The difference is largest on archives. An online unzipper has to take the whole gigabyte before it can list anything. Foretaste reads the index at the end, which for a 40 MB archive is about 67 KB, and reports the real figure on screen each time rather than repeating that one.
It also works on files behind a login. The request carries your own cookies, because it is your own browser making it, so a file on a company portal or a university site opens the way the site intended.
The questions people ask
Can you see inside a file before downloading it?
Yes, with a browser extension. Foretaste reads the file straight from its link: right-click it, choose Open with Foretaste, and the contents appear in a panel over the page. For a ZIP it reads only the index at the end of the archive, which is a few kilobytes rather than the whole file.
How can I check what is inside a ZIP file without downloading it?
A ZIP keeps its index at the very end. If the server honours range requests, a tool can fetch just that last chunk, typically a few kilobytes, and list every file inside without transferring the rest. Foretaste does this in one click and shows the byte count it actually used.
Is it safe to preview a file before downloading it?
Foretaste is not antivirus software and cannot tell you whether a file is malicious. What it can tell you is when a file is not what its name says: it checks the leading bytes against the signatures real formats begin with, so a file called report.pdf that is actually an executable is named as one. Every file is read inside your own browser tab.
How do I stop downloading files just to view them?
Install the Foretaste extension on Chrome, Edge or Firefox. When you right-click a file link and choose "Open with Foretaste", the file is read in your browser without being saved to disk. You only download it if you later decide you want to keep it.
Can I view files online without uploading them to a third-party service?
Yes. Foretaste reads files in your own browser without sending them to any server. Online viewers typically require you to upload the file to their cloud, which is slow, uses storage, and means your document has been somewhere you did not choose. Foretaste has no file-processing server: every byte is read locally.
Can I open files from a website without saving them to my computer?
Yes. Foretaste fetches the file from the website it already lives on and reads it in the browser tab. If you close the tab, no trace of the file is left on your machine. You can choose to save it to disk at any point, but nothing saves automatically.