SeaMonkey is described as 'Web-browser, advanced e-mail, newsgroup and feed client, IRC chat, and HTML editing in one application. Itis built on the open source Mozilla Gecko engine, the same code which underlies Thunderbird and is the base for the Firefox browser' and is a well-known app in the Web Browsers category. There are more than 100 alternatives to SeaMonkey for a variety of platforms, including Windows, Mac, Linux, Android and iPhone. The best alternative is Mozilla Firefox, which is both free and Open Source. Other great apps like SeaMonkey are Thunderbird (Free, Open Source), Google Chrome (Free), Brave (Free, Open Source) and Vivaldi (Free).