A simple, private PDF reader
Most devices can open PDF files, but not always conveniently: a work laptop may lack a reader, a shared computer may open files in an app that keeps a history, and some phones download a PDF into a folder you then have to find. This viewer opens a PDF directly in the page. Choose the file or drag it onto the drop area and the first page appears. The document is read from your own storage and drawn by PDF.js, the open-source PDF engine built into Firefox, which this site serves itself. Nothing is uploaded and nothing is kept after you close the tab.
Moving around the document
Use the Prev and Next buttons, or type a page number and press Enter to jump straight to it. On a computer, click or tab to the page area and the left and right arrow keys and Page Up and Page Down also change pages. The zoom menu offers Fit width, which fills the space available and adapts when you rotate a phone or resize the window, plus fixed sizes from 50% to 200%. At larger sizes the page area scrolls sideways so you can pan across it.
Sharp on every screen
Phones, tablets and many laptops have high-density displays with two or three physical pixels per CSS pixel. The viewer draws each page at the full resolution of your screen, so text looks crisp rather than blurry, and it redraws the page whenever you zoom instead of stretching an image.
What it does not do
This is a reader, not an editor. It does not fill in forms, add comments or sign documents, and text selection is not available because pages are drawn as images on a canvas. Password-protected PDFs need to be unlocked first. For other jobs, use the related tools: split PDF to extract pages, merge PDF to combine documents, and PDF to image to save a page as a picture.
Privacy
Because the file is never sent anywhere, the viewer is a reasonable way to check a document you have received before forwarding it, on any device with a modern browser.