The best alternative to Signal is Delta Chat, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Signal and many of them are so hopefully you can find a suitable replacement. Other interesting alternatives to Signal are Conversations, Linphone, ArcaneChat and Berty.
Provides a chat experience over email, with all messages and contacts stored on user devices, open source code, group media support, and compatibility with any provider. No central servers, no tracking, works without SIM, and can be used by anyone just via email.
Conversations is a privacy focused, open source XMPP Texting [Jabber] client for Android 4.0+ smart phones with wife-approved easy encryption [OTR, OMEMO, or GPG].
Uses OMEMO, OTR, and/or GPG encryption and is decentralized. Also it's open source.
From my point of view Conversations is the most user-friendly XMPP client for Android. It also does not require a phone number, is decentralized and looks just great.
Has End-to-End encryption by default. Is decentral/federated so not to block or shutdown.
Linphone is one of the most famous open source softphones in the world. It is fully SIP-based, for all calling, presence and IM features.
ArcaneChat is a Delta Chat client and was created with a focus on usability, good user experience, and saving data plan. Also the app usually experiments with new features that eventually might get added to the official Delta Chat client.
Berty is a secure peer-to-peer messaging app that works with or without internet access, cellular data or trust in the network. Berty is a privacy-first messaging application built on top of the Berty Protocol.
Self-hosted communication platform with secure audio, video, chat, web conferencing, screensharing, advanced encryption, and metadata privacy, running on user-controlled servers, supporting web and mobile apps, and eliminating third-party data exposure.
Status combines a private messenger, secure crypto wallet, and Ethereum Web3 DApp browser into one powerful communication tool. Chat with friends and growing communities. Buy, sell, store, and exchange digital assets.
decentralization, Switzerland, P2P
Dino is a modern open-source chat client for the desktop. It focuses on providing a clean and reliable Jabber/XMPP experience while having your privacy in mind. Using GTK+/Vala.
signal-cli is a commandline interface for the Signal messenger. It supports registering, verifying, sending and receiving messages. signal-cli uses a patched libsignal-service-java, extracted from the Signal-Android source code.
Germany
EU
France
Estonia
The concept of DeltaChat is so simple and brilliant! Secure chat on top of an infrastructure that is already there: Email and the IMAP-protocol.