
Description: PDF4Free is a free, open-source PDF editor that allows users to view, create, edit, convert, encrypt, sign and print PDF documents. It offers basic PDF editing features like adding text, images, shapes, whiteout, highlights, annotations and digital signatures.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Nitro PDF Pro is a premium PDF editor that allows you to create, edit, convert, sign, and secure PDF files. It has an intuitive interface and advanced editing tools for annotating, rearranging pages, adding form fields, reviewing documents and more.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API