What are some alternatives?
When comparing Keybase for Mobile and Ruler, you can also consider the following products
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
MailHog - MailHog is an email testing tool inspired by MailCatcher, but easier to install.
MyChat - Secure instant messenger for any network
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
MagicPad - Free, simple, and private, offline text encryption suite.
Fluid Browser - Fluid Browser is a Floating Transparent Browser for Mac or Floating Transparent Browser for Mac