You can read a PDF, a Word file, a spreadsheet, a deck or an image on any device without installing anything. Whether you are racing a deadline, juggling classes, or just need to check what is inside a file, downloading and configuring a separate viewer for each format wastes time. Doconut.app opens the file in the browser tab you already have open, free and without an account, and deletes it when you are done.
This guide walks through that workflow, and is equally clear about where it stops. Doconut.app is a viewer: it does not convert files, does not edit them, has no accounts and no paid tier, and takes one file at a time. Knowing the edges is what makes it useful rather than disappointing.
1. The Real Pain Point: Why “No Installation” Matters for Mobile Professionals
The hidden cost of traditional document viewers
When a field engineer gets a CAD drawing on a tablet, a marketing analyst needs to skim a quarterly PowerPoint on a commuter train, or a student wants to glance at a PDF lecture note on public Wi‑Fi, the usual workflow looks like this:
- Locate the file – often buried in an email attachment, cloud storage, or a shared drive.
- Download the file – saps bandwidth and can be blocked by corporate firewalls.
- Install a viewer – Adobe Reader, Microsoft Office, or some niche image tool.
- Configure settings – security prompts, plug‑in updates, license activation.
- Open the file – hoping the installed version actually supports the format.
Each step adds time, risk, and friction. Mobile pros often run on limited data plans, and corporate IT policies may bar unapproved software. Students on shared computers can’t count on admin rights. The result? A lost minute—or worse, a missed deadline—because the viewer isn’t ready.
How Doconut App eliminates every step
Doconut.app's browser-based viewer removes steps 2 to 4:
- Zero plugins – the pages render in plain HTML and JavaScript, so any modern browser displays them. Nothing to install, no extension, no admin rights.
- Encrypted upload – the file travels to us over HTTPS.
- Nothing kept – the file is rendered in a temporary session tied to your browser and deleted from our servers when that session ends. There is no library, no history and no account it could be attached to, because there is no account at all.
The honest version of the security story is that one sentence: we do not keep it. We are not offering encrypted long-term storage, because we are not offering storage.
2. Step‑By‑Step Workflow: From File Link to Instant View
Step 1 – Go to the page for your format
There are seventeen viewers, one per family, and each has its own page: PDF, Word, Excel, PowerPoint, CAD, PSD, email, Visio, Project, TIFF, eBook and the image and text viewers. The home page accepts anything and routes it for you.
There is no link to share and no upload API here. Each person opens the file themselves, in their own session. If you need a link a recipient can click, you are describing the SDK sitting inside your own application, not this site.
Step 2 – Drop the file on the page
Drag it in, or click to pick it. One file at a time — there is no batch upload, no queue and no ZIP handling. The uploader checks the extension and the size before it sends anything, so a file that is not going to work is refused straight away rather than halfway through.
Supported formats run to 70+ extensions: PDF, DOC/DOCX, ODT, RTF, XLS/XLSX, CSV, ODS, PPT/PPTX, ODP, VSD/VSDX, MPP, MPX, DWG, DXF, DGN, PSD, EML/MSG, EPUB, JPEG, PNG, GIF, BMP, SVG, TIFF, WebP, DNG, EPS, TXT, XML, HTML and the macro-enabled and template variants of the Office formats.
The size ceiling is not one number, and this is the thing most worth knowing before you rely on it. It belongs to the format:
| Limit | Formats |
|---|---|
| 25 MB | PDF, PSD, Visio, TIFF, EPUB, and all the image formats |
| 20 MB | Excel, PowerPoint, Project |
| 15 MB | Word, RTF |
| 10 MB | CAD, email |
| 5 MB | XML, HTML, plain text |
Go over and the message names the exact limit for the format you tried. CAD is the one that catches people out: 10 MB is not much for an issued drawing.
Step 3 – Interact with the document instantly
When the viewer loads, you get the controls a reader actually needs:
- Zoom and navigation – pinch to zoom on touch devices, mouse wheel on a desktop, jump to a page number, fit the page to the window.
- Print – Ctrl+P, or Cmd+P on a Mac. It prints the pages exactly as they render on screen.
- Camera and image details – in the vector and raw image viewer, a photograph's EXIF sits beside the image: dimensions, colour space and the camera settings a DNG carries. Embedded ICC profiles are applied, so print-prepared colour stays correct.
What is not there: editing, annotating, signing, and any kind of export. The viewer draws the file; it does not write a new one. If you need the document in a different format, that is the sibling site OnlineDocumentViewer.com.
Step 4 – Close the tab
When the viewing session ends, the file is deleted from our servers. There is nothing to come back to later, nothing to log into, and nothing for us to hand over.
Why it matters: Not keeping something is the strongest guarantee available about it. What we cannot offer you is a certificate: Doconut.app holds no ISO 27001, no SOC 2 and no HIPAA attestation. If your organisation requires one, no free hosted viewer is the right answer — run the SDK on your own infrastructure instead, where the file never leaves your network.
3. What actually happens to your file
On the way in
The upload runs over HTTPS. That protects the file in transit between your browser and our servers, which is the part of the journey a public network can see.
While it is open
It is rendered in a temporary session tied to your browser. It is not attached to a profile, because there are no profiles, and it is not indexed or searchable by anyone else.
Afterwards
It is deleted when the session ends. That timing is ours, not yours — there is no retention setting to configure on a free site with no accounts in it. If a fixed, auditable retention policy is a requirement, that is an argument for hosting the viewer yourself rather than for using this one.
Bottom line: upload something you would not mind reading on a train, and for anything tighter than that, keep the rendering inside your own network.
4. Performance That Keeps Up With On‑The‑Go Demands
Where the work happens
The rendering is done on our servers, not on your device. That is deliberate, and it is why a ten-year-old laptop opens a layered PSD as happily as a new one: your machine only has to display pages that arrive ready to draw.
The trade-off is that the file has to get to us first. On a slow connection a 25 MB PSD takes as long to upload as anything else that size, and the per-format ceilings exist partly for that reason.
Result: the device stops being the limiting factor. The connection and the file size still are.
5. Customisation: this is the SDK's job, not the free site's
Everything above describes Doconut.app, our site. Nothing on it is configurable by you: it is our page, with our styling, and it has no API.
The separate answer for developers is the Doconut SDK, the licensed .NET component that renders the same formats inside your own application. That is where branding, permissions, storage and access rules belong — they only mean anything when you control the surrounding app and the servers it runs on. The SDK covers 75 extensions, two more than the free viewers, because it includes the DICOM plugin for medical imaging that the free sites deliberately leave out.
Its separately licensed plugins are Annotation, Converter, DICOM and Search. Controlled printing is not among them; it is part of the viewer itself.
Why it matters: the free site answers "I cannot open this file". The SDK answers "my users cannot open this file inside my product". They are different problems with different price tags.
6. Real‑World Scenario: A Student’s Quick‑Study Session on a Campus Laptop
Picture Maya, a second-year engineering student with three files to read on a library machine: a PDF of lecture slides, a CSV of lab results, and a high-resolution photograph of a circuit diagram. She has no admin rights to install Adobe Reader or Office, and the disk is nearly full.
- She opens the PDF viewer and drops the lecture slides on it. They render; she zooms in on one diagram.
- She closes the tab, which deletes the PDF from our servers, and opens the Excel viewer for the CSV. One file at a time — there is no study pack and no single link that holds all three.
- The circuit photograph goes to the image viewer, where she zooms in and reads the EXIF beside it for the camera settings.
- She leaves. Nothing is on the library machine, because nothing was downloaded, and nothing is on our servers either.
Maya installed nothing and signed up for nothing. The friction that remains is real and worth naming: three files meant three uploads, and if the slide deck had been a 30 MB PDF it would have been refused at the door.
Key Takeaways
- Zero-installation viewing removes the downloads, the installs and the need for admin rights.
- HTTPS upload, and deletion when the session ends — no storage, and therefore no stored-file encryption to promise and no certification to claim.
- 70+ extensions, with a size ceiling that belongs to the format: 25 MB down to 5 MB, not one number for the site.
- Server-side rendering means an old device opens a heavy file, but the file still has to be uploaded first.
- Zoom, page navigation, Ctrl+P printing, and EXIF beside the image in the raw and vector viewer.
- No editing, no conversion, no batch, no accounts. Conversion is OnlineDocumentViewer.com; embedding is the SDK.
Conclusion
If you just need to read a file today, start at Doconut.app — it costs nothing and asks for nothing.
If you need that viewing inside a .NET application of your own, evaluate the Doconut SDK with your own representative files and your own security requirements. Test the awkward ones: the issued drawing, the layered PSD, the 200-page scan.