PDFo is described as 'A fast and easy online PDF toolkit that lets you merge, compress, convert, split, and edit PDF files directly in your browser—no installation required' and is an website in the office & productivity category. There are more than 50 alternatives to PDFo, not only websites but also apps for a variety of platforms, including Windows, Mac, SaaS and Android apps. The best PDFo alternative is Stirling-PDF, which is both free and Open Source. Other great sites and apps similar to PDFo are BentoPDF, Adobe Acrobat DC, Breeze PDF and Sejda.