PDF Viewer's name belies the power under its hood. This is more than just a viewer app. PDF Viewer includes powerful PDF editing tools on par with, and in some cases more extensive than, some of the best PDF apps I’ve tried. That's not to say that there aren't a few rough edges and limitations, but for a free app, PDF Viewer should suit the PDF viewing and editing needs of most people.
PDF Viewer was created by PSPDFKit. You may not have heard of PSPDFKit before, but there's a good chance that you have used its PDF engine, which is built into many other apps This explains why an app as feature-rich as PDF Viewer is free. It's designed to showcase PSPDFKit’s PDF frameworks to potential customers.
The core functionality that I expect from any PDF viewer app is all here. You can open PDF files from multiple sources depending on the apps you have installed or send a PDF to PDF Viewer from another app using the 'Open In' command from the Share Sheet. Once open, you can navigate the pages of PDFs by swiping from page to page or scrolling though thumbnails of those pages for longer documents. One nice customization touch is that you can set PDF Viewer to scroll through PDFs horizontally or vertically.
The viewing experience is further customizable in settings. There are three different themes that can be applied to PDFs - standard black text on a white background, a sepia-toned background with black text, and white text on a black background. You can also control brightness and whether PDFs scroll page-by-page or continuously. Overall, the viewing experience and customization is on par with other PDF apps I've used.
PDF Viewer also includes a full suite of editing tools including:
- Customizable pen and marker tools with a companion eraser tool;
- Text markup tools with regular and squiggle underlining, strikeout, and highlighting;
- Tools for adding text to a PDF, creating text call-out bubbles, and signing PDFs;
- A sticky note-style comment tool;
- Arrow, line, and shape tools;
- Photo, stamp, and audio annotation tools;
- A multi-item selection tool; and
- Undo and redo buttons.
That's a lot of editing tools. In fact, there are more editing tools in PDF Viewer than in many other PDF apps.
The final major component of PDF Viewer is the Document Editor. Tapping the Document Editor button displays thumbnails of each page in your PDF. In this mode, you can add, delete, duplicate, move, and rotate pages. You can also create a new document from any pages you select.
PDF Viewer is not without some limitations. Annotations can only be exported using the 'Open In' option from the Share Sheet, which duplicates an editable or flat copy of your PDF, resulting in two copies of the same document in two apps. Another limitation is that there is no mechanism in PDF Viewer to sync PDFs among multiple iOS devices. Nor is there a Mac version. Finally, PDF Viewer froze and crashed a few times in my testing when leaving and returning to the app in the middle of editing a PDF. I didn't lose any data, but this does appear to be a bug.
That said, I am impressed with PDF Viewer. It stacks up well against the features of popular PDF apps like PDF Expert and PDFpen, which is impressive for a free app. I would be concerned about the sustainability of a free app of PDF Viewer's complexity, except for the fact that it's intended as a showcase for PSPDFKit's development frameworks. The byproduct of that business model is a sophisticated PDF viewing and editing app that is entirely free, which is great for iOS users.
PDF Viewer is available on the App Store as a free download.