SureSpot is described as 'open source encrypted messenger designed to make encrypted messaging simple and accessible to anyone' and is an app in the Security & Privacy category. There are more than 25 alternatives to SureSpot for a variety of platforms, including Android, iPhone, Android Tablet, Windows and iPad. The best alternative is Telegram, which is free. Other great apps like SureSpot are Signal (Free, Open Source), Element (Free Personal, Open Source), Tox (Free, Open Source) and Zulip (Free Personal, Open Source).
Signal is a messaging app with an unexpected focus on privacy, combined with all the features expected from a modern IM app. Signal has received a lot of praise from all around the world for its security and privacy-respecting technologies.
Element is a secure collaboration and messaging app based on the Matrix protocol. It’s decentralised to deliver digital sovereignty, and based on an open standard for easy connections and interoperability. It is end-to-end encrypted by default.
Utopia P2P Ecosystem. Utopia is a feature-rich platform that is specifically designed to protect privacy of communication, confidentiality, and security of personal data. Utopia is a decentralized network, with no central server involved in data transmission or storage.
ChatSecure is a free and open source messaging app that features OTR encryption over XMPP. You can connect to your existing accounts on Facebook or Google, create new accounts on public XMPP servers(including via Tor), or even connect to your own server for extra security.
An alternative Telegram client based on TDLib, with higher speed, slicker animations and experimental features. The goal of Telegram X is to reinvent Telegram and explore new frontiers in speed, ease of use, quality of animations and all other aspects.