How to view files online, with nothing to install

How to open a file online: the short answer

Pick the viewer for your file type, upload the file and click "View" in the list. The content opens in a window over the page itself, with no new tab and no download: the PDF shows page by page, the photo at full size, audio and video with a player, the CSV spreadsheet as a table. Close it with the ✕ or the Esc key. The exception is the .ics invite, which opens right below the list and closes with "Back." Nothing is sent to a server.

Which files you can view online

• PDF: each page becomes a sharp image (up to 1100 px wide), which works the same on desktop and phone, even where the browser's own PDF reader fails.
• Images: JPG, PNG, WEBP, GIF, BMP, SVG and AVIF directly; HEIC/HEIF (iPhone photos) and TIFF are converted on the fly to display.
• Audio: MP3, WAV, M4A, AAC, OGG, OPUS and FLAC, in the browser's own player.
• Video: MP4, MOV, WEBM, MKV, AVI and M4V, in the browser's own player.
• Documents: EPUB e-books, HTML pages and Markdown text, shown as a formatted page in an isolated frame.
• Spreadsheet: CSV, laid out as a table (XLSX doesn't open in this viewer).
• Text and data: TXT, JSON and YAML, as readable text.
• Calendar invite .ics: title, when (with time zone), where, organizer, attendees, status and a "Repeats" label for recurring events, without adding anything to your calendar.

Step by step to open a file online

1. Open the viewer for your file's type (PDF, image, audio, video, document, spreadsheet, text or calendar).
2. Upload the file: drag it onto the "Drag your files" area or click "Select files." It appears in a list.
3. Click "View" (for an .ics invite, the button is "Open"). The content opens over the page; a HEIC or TIFF takes a moment longer, because it's converted first.
4. Read, play, watch or scroll through the table. To close, click the ✕ or press Esc (for the .ics invite, click "Back"); the file stays only on your device.

PDFs and images: how this differs from opening in an app

The PDF is drawn page by page as an image, so you can read and scroll on any device, but you can't select text or fill forms here: it's a reading viewer. For photos, the advantage is the iPhone's HEIC and the scanner's TIFF, which many computers won't open: here they're converted to JPG on the fly, only for display, and the original is left untouched.

Audio and video: it depends on what your browser can play

The player is the browser's own, with no conversion. MP3, WAV, MP4 and WEBM play everywhere; MKV, AVI, FLAC and OPUS are accepted but may not play in every browser (Safari is the most restrictive). If the file opens with no sound or no picture, your browser doesn't support that format; convert it to MP4 or MP3 first. The steps are in how to convert a video to MP4.

E-books, HTML, Markdown, CSV and text

EPUB, HTML and Markdown become a formatted page inside an isolated frame that runs none of the code embedded in the page. CSV shows as a table with rows and columns, and TXT, JSON and YAML show as plain text, with nothing executed. Word and Excel don't belong here: they have the Office viewer, which reproduces the formatting faithfully but, unlike the others, opens the file on our server. Its guide is how to open Word, Excel and PowerPoint online without Office. PSD, DXF, STL, notebooks, emails and XML invoices, on the other hand, open in the browser through other viewers: how to open files your computer can't open.

Calendar invites (.ics) without accepting anything

Got an .ics invite and don't want it landing in your calendar just to see what it's about? The calendar viewer lists each event with title, date and time in the right time zone, location, organizer, attendees and the status recorded in the invite. You read, decide, and only then accept it in your own app, if you want to.

Common problems and limits

• The file doesn't show up in the viewer's list: the format isn't accepted by that viewer (for instance, XLSX in the spreadsheet viewer, DOCX in the document viewer).
• Video with no sound or a black screen: the browser can't read the kind of compression used in that file. Convert it to MP4.
• A large PDF is slow: each page is drawn on your device; a 500-page book takes a while.
• Upload limit: 2 GB per file; on phones, the browser's memory may run out first.
• Read-only: no editing, signing or filling; for that, use the editing tools.
• You see "Could not open this file.": the file is damaged or isn't what its extension says (a .pdf that is really something else, for instance).

All of these viewers run inside your browser: the file is opened on your own device and is never uploaded to any server. That's why you can look at private documents with peace of mind.