Somebody sends you a file and your machine has nothing that opens it. OnlineDocumentViewer renders it in a browser tab instead — free, no sign-up, and the file deleted when you close it.
Here is what it covers, where the limits are, and what it will not do.
What it opens 🌟
Seventeen viewers, 70+ extensions between them, with the size ceiling set per format:
| Viewer | Limit |
|---|---|
| PDF, PSD, Visio, TIFF, EPUB, images | 25 MB |
| Excel, PowerPoint, Project | 20 MB |
| Word, RTF | 15 MB |
| CAD, email | 10 MB |
| HTML, XML, plain text | 5 MB |
It is a fixed catalogue rather than everything. Over the limit or outside the list, the upload box says so instead of accepting the file and failing later.
Free, with no account and no paid tier — the thing that costs money is the SDK on Doconut.com, which is a different product for developers.
How it works
Upload: drag the file onto the viewer page for its format, or drop it on the home page and it is routed for you.
Read: page, zoom, fit to window, print. Search works where the document carries a text layer. CAD drawings add layer control and measurement.
Close: the file is deleted from the server. There is no account, no library and no second copy.
One file per upload. There is no batch, no ZIP and no queue — if you have three documents, that is three uploads.
The technology behind it: the Doconut engine
The rendering runs on the server, on the Doconut .NET library. The browser receives pages rather than the original file, which is why a DWG opens on a phone that has never had CAD software on it, and why nothing inside the document executes on your machine — a macro-enabled DOCM renders, and the macros do not run.
That same engine is sold separately as an SDK for teams embedding a viewer in their own product. It renders 75 extensions across 18 families; this website accepts 73 of them, leaving out .dcm and .ima — DICOM, a separately licensed plugin.
Who it is for
Students: lecture PDFs, EPUB texts and decks, on whatever machine is free.
Professionals: a contract, a cost plan or a drawing sent by someone who assumed you had the software.
Educators: material handed out as a file that opens here, rather than an attachment half the class cannot read.
What it does not do
It views. No editing, no annotation, no signing, no OCR. If you need the contents in another format, the converters handle PDF, Word, Excel, PowerPoint, CAD, email and common images — that is a separate set of pages.
Start at the viewer hub.