Open Source Mobile Operating Systems Chat Software
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Chat Software for Mobile Operating Systems
Browse free open source Chat software and projects for Mobile Operating Systems below. Use the toggles on the left to filter open source Chat software by OS, license, language, programming language, and project status.
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gSOAP Toolkit
Development toolkit for Web Services and XML data bindings for C & C++
The gSOAP toolkit is an extensive suite of portable C and C++ software to develop XML Web services with powerful type-safe XML data bindings. Easy-to-use code-generator tools allow you to directly integrate XML data in C and C++. Serializes native application data in XML. Includes WSDL/XSD schema binding and auto-coding tools, stub/skeleton compiler, Web server integration with Apache module and IIS extension, high-performance XML processing with schema validation, fast MIME/MTOM streaming, SOAP and REST Web API development, WS-* protocols (WS-Security, WS-Policy, WS-ReliableMessaging, etc), XML-RPC and JSON. Licensed under GPLv2. Visit the developer center with guides, tutorials, and examples at www.genivia.com/dev.html The documentation of the toolkit, libraries, plugins and more is available at www.genivia.com/docs.html Commercial-use licenses and expert technical support services are available at competitive pricing levels, please visit www.genivia.com/products.html -
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Tinode Instant Messaging Server
Instant messaging platform
Instant messaging server. Backend in pure Go (license GPL 3.0), client-side binding in Java, Javascript, and Swift, as well as gRPC client support for C++, C#, Go, Java, Node, PHP, Python, Ruby, Objective-C, etc. (license Apache 2.0). Wire transport is JSON over websocket (long polling is also available) for custom bindings, or protobuf with gRPC. Persistent storage is any one of RethinkDB, MySQL or MongoDB. A third-party unsupported DynamoDB adapter also exists. Other databases can be supported by writing custom adapters. Tinode is not XMPP/Jabber. It is not compatible with XMPP. It's meant as a replacement for XMPP. On the surface, it's a lot like open source WhatsApp or Telegram. Version 0.17. This is beta-quality software, feature-complete and stable but probably with a few bugs. Follow instructions to install and run or use one of the cloud services provided. -
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Session for Android
A Decentralized, Onion Routed, Private Messenger
Session Android is the official mobile client for Session, a privacy-first messaging protocol that enables secure, anonymous messaging without requiring phone numbers, email addresses, or centralized user accounts. Built natively for Android, the app lets users send and receive end-to-end encrypted text messages, voice notes, images, and attachments in both one-on-one and group chats, all while routing data through a decentralized onion-routing network designed to protect not just message content but also metadata like sender ID, timing, and network location. The Android client integrates seamlessly with Android’s notification system and background services so that you can stay connected without exposing your identity or compromising privacy, and it supports features such as message reactions, search within chats, profile and contact management, and local message storage encrypted at rest. -
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Signal iOS
A private messenger for iOS
Signal is a free, open source, messaging app for simple private communication with friends. Say "hello" to a different way of chatting: Signal is all about privacy, but with all the features you expect from a chat app. State-of-the-art end-to-end encryption (backed by Signal's open source protocol) keeps your chats safe. Neither we can read your messages or listen to your calls, nor anyone else. Privacy is not an optional mode, it is how Signal works. In all your messages, all your calls, forever. Send and receive messages, voice memos, photos, videos, GIFs and files for free. Signal uses your phone's data connection so no SMS or MMS charges are incurred. Make crystal clear calls and video calls to people who live across town or across the ocean with no long distance charges. Add a new layer of expression to your chats with encrypted trading cards. You can also create and share your own sticker packs. -
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SmsForwarder
Monitors Android mobile phone text messages, calls, and notifications
SmsForwarder is an Android application designed to monitor incoming communications such as SMS messages, phone calls, and app notifications, and then automatically forward them to configured destinations based on user-defined rules, making it ideal for remote monitoring, backup, or automation scenarios. Users can set custom logic so that certain messages or notifications trigger forwarding to group chat bots (like DingTalk or enterprise WeChat), webhook endpoints, email, push services (PushPlus, Bark), Telegram bots, and other channels, allowing flexible integration with communication workflows. In addition to basic forwarding, the app’s rule-based engine can filter messages, enabling selective forwarding based on content, sender, or event type, and it can even push details like call logs or device battery status. The tool’s functionality extends to remote control features, which allow a paired server or client to query messages, calls, contacts, and more. -
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Bunny
A Discord mobile app client modification
Bunny is a client modification for Discord’s mobile apps. It was developed to extend or customize the mobile Discord experience through a separate loader-based setup. The project supports Android installation through root or non-root tooling and iOS installation through tweak or prepatched app options. Developers can clone the repository, install dependencies, build the bundled script, and load it through a custom URL in Discord’s developer settings. The workflow is designed for people who want to test mobile Discord modifications directly on a device. The repository is now archived and no longer actively maintained, so it is best viewed as legacy code for reference or experimentation. -
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Sideband
LXMF client for Android, Linux and macOS to communicate with people
Sideband is a privacy-focused, peer-to-peer mesh messaging protocol and platform that allows users to communicate directly over local networks or the internet without servers. It emphasizes metadata resistance and secure message delivery, working effectively in offline, low-bandwidth, or disaster recovery scenarios. Built-in Rust, Sideband supports encrypted group messaging, file transfers, and network self-discovery. It is ideal for use in community networks, crisis response, and decentralized communications infrastructure. -
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Element X Android
Android Matrix messenger application using the Matrix Rust SDK
Element X Android is a modern, reimagined Matrix-protocol client designed for Android that provides secure, decentralized communication with a focus on performance, polished UI, and extensibility. Built as the successor to earlier Matrix clients, Element X blends fast native Android development with a feature-rich experience that supports end-to-end encrypted messaging, voice and video calls, threaded conversations, and file sharing across federated Matrix servers. Unlike proprietary messaging apps, Element X connects to any compliant Matrix server, letting individuals host their own or join communities without centralized control, while still benefiting from robust cryptographic protections that ensure only intended recipients can read conversations. The app’s UI emphasizes responsiveness and ease of use with modern navigation patterns, customizable themes, and intuitive controls for group chats and spaces (Matrix’s equivalent of servers or room collections). -
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Telegram for Android
Telegram messenger for Android
Telegram is a wonderful and private messaging app that offers simple, fast, secure and synced messaging for all your devices. It delivers messages faster than any other application; cloud-based so you can access your messages from any device; and very secure, with messages heavily encrypted and could even self-destruct. Telegram is simple and fun to use, with powerful photo and video editing tools as well as an open sticker/GIF platform to let you express yourself fully. It’s also incredibly powerful. Whether you’re setting up a group chat for up to 200,000 members or sharing large videos or documents, Telegram is up to the task. Best of all it’s completely free and open source, with no ads or subscription fees. -
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Facebook SDK for Android
Used to integrate Android apps with Facebook Platform
This open-source library allows you to integrate Facebook into your Android app. Integrate your Android app with Facebook to build engaging social apps by using the Facebook SDK for Android. To learn more about using Facebook development tools. The current version of the Facebook SDK for Android is version 11.2.0 and requires the Android API 15. Code and samples for the Facebook SDK for Android are available on GitHub. A secure and convenient way for people to log into your app or website by using their Facebook credentials. Enable people to post to Facebook from your app. People can share, send a message, and share to stories. Understand people's actions in your app and measure the effectiveness of your Mobile App Ads. Get data in and out of Facebook's social graph, query data, post stories, upload photos and perform other tasks. -
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Rocket.Chat Android
Legacy mobile Rocket.Chat client in Kotlin for Android
Rocket.Chat is a free and open-source team chat collaboration platform that allows users to communicate securely in real-time across devices on the web, desktop or mobile and to customize their interface with a range of plugins, themes and integrations with other key software. By opting for Rocket.Chat, users also benefit from free audio and video conferencing, guest access, screen and file sharing, LiveChat, LDAP Group Sync, two-factor authentication (2FA), E2E encryption, SSO, dozens of OAuth providers and unlimited users, guests, channels, messages, searches, and files. Users can set up Rocket.Chat on the cloud or by hosting their own servers on-premises. -
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Tox
A New Kind of Instant Messaging
Tox is a peer to peer (serverless) instant messenger that focuses on security and privacy. In today's world where digital surveillance is rampant, Tox offers users a communication software alternative that's free from prying eyes and ears, and is, quite literally free and without advertising. Tox comes with all the great features you'd expect from an instant messenger application, including voice calls, video calls, file sharing and screen sharing. Everything done on Tox is encrypted using open-source libraries so you can be assured of completely private conversations. It also has no central servers that can be raided, shut down, or forced to turn over data. There are no corporate interests, no hidden agendas-- just simple, secure and easy to use messaging. -
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Signal
A private messenger for Android
Signal-Android is the official open-source Android client for Signal, a secure messaging app focused on end-to-end encryption and privacy. Developed by the Signal Foundation, it enables private messaging, voice, and video calls, without storing user data. Signal uses the Signal Protocol for encryption and does not collect metadata, making it one of the most privacy-focused communication platforms available. -
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Signal Server
Server supporting the Signal Private Messenger applications on Android
Signal Server is the official backend server component that supports the Signal Private Messenger ecosystem on Android, iOS, and desktop platforms, serving as the trusted message relay, contact discovery, and push notification hub while the clients handle end-to-end encryption. Built in Java and licensed under the AGPL-3.0 license, this server software handles protocols for delivering encrypted messages, synchronizing user metadata like public keys and push tokens, and providing REST and service APIs for the client apps to interact with. Although cryptographic operations and message confidentiality are managed by the client side using the Signal Protocol, the server ensures message routing, user registration, and group updates without having access to the decrypted contents. Its codebase is public to ensure transparency and auditability for a security-focused community willing to inspect how message metadata and delivery mechanisms are implemented. -
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Smoke Crypto Chat Messenger for Android
Smoke: Android Crypto Chat Messenger
Smoke is an encrypting chat messenger for Android written in Java. Please read the Web site for more information: https://textbrowser.github.io/smoke/ (original, current) https://www.amazon.com/dp/3752691999/ https://smokeappope.sourceforge.io/ (old, third party archive) Smoke App OPE - Open Personal Encryption Download Android APK Installer: https://sourceforge.net/projects/smokeappope/files/ Smoke Source: https://github.com/textbrowser/smoke SmokeStack Source: https://github.com/textbrowser/smokestack (Android) https://github.com/textbrowser/spot-on (Desktop) Smoke appears to be one of the first projects with an open source mobile encrypting chat server., an decentralized and easily-configurable chat server. Smoke is known as the first mobile McEliece Messenger: https://tarnkappe.info/artikel/english/mceliece-messaging-smoke-crypto-chat-the-first-mobile-mceliece-messenger-published-as-a-stable-prototype-worldwide-279847.html -
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bitchat
bluetooth mesh chat, IRC vibes
bitchat is a decentralized peer-to-peer messaging app that operates over Bluetooth mesh networks, enabling local group chats without the need for internet, servers, or phone numbers. It is designed with privacy and security in mind, offering encrypted private messages and channels alongside a public local chat that requires no registration. -
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Bitchat
Bluetooth mesh chat, IRC vibes
BitChat is a decentralized, peer-to-peer encrypted messaging app built by Jack Dorsey’s Permissionless Tech. It uses Bluetooth Low Energy mesh networking to relay messages without internet, servers, accounts, or phone numbers. Messages are end-to-end encrypted (Curve25519 + AES‑GCM) and the app includes a panic mode to erase data quickly. -
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Element iOS
A glossy Matrix collaboration client for iOS
Element iOS is the official iPhone and iPad client for the Element communication platform, which is built on the Matrix open standard for secure, federated messaging and collaboration. The app provides users with a rich environment for encrypted messaging, group chats, voice and video calls, file attachments, and room creation, all while interoperating seamlessly with the wider Matrix network — meaning you can communicate across servers and services that adopt the same protocol. On iOS, Element handles user identity, room membership, and end-to-end encryption with strong key management, allowing users to hold secure conversations that only intended participants can read, even across federated instances. The interface adheres to modern iOS paradigms, offering intuitive navigation, notifications, threaded replies, message reactions, customizable themes, and support for rich media rendering. -
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Session for iOS
A Decentralized, Onion Routed, Private Messenger
Session iOS is the native iPhone and iPad client for the Session secure messaging ecosystem, engineered to bring private, anonymous communication to Apple’s mobile platforms without relying on phone numbers or email addresses. The app supports encrypted one-on-one and group chats, voice messages, file and image sharing, and threaded conversations, all delivered over a decentralized onion network designed to conceal metadata such as sender identity, message timing, and network path. On iOS, Session integrates with Apple’s notification and background execution frameworks so that messages arrive reliably while preserving privacy protections, and it supports Face ID/Touch ID unlock to guard access to local message storage. Its interface follows iOS conventions for navigation, attachments, and user interaction, making secure messaging feel natural to Apple users while maintaining rigorous cryptographic standards. -
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Zulip
Powerful open source team chat application
Zulip is a powerful open source group chat application that combines the immediacy of real-time chat with the productivity benefits of a threaded conversation model. Zulip’s unique threading model allows users to easily catch up on important conversations, helping to save time and increase productivity. -
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Berty
Berty is a secure peer-to-peer messaging app
Berty is an open, secure, offline-first, peer-to-peer and zero trust messaging app. Berty is an encrypted and offline peer-to-peer messenger with no central server. Connect with or without an internet connection, message for free, and avoid surveillance and censorship. Berty is fresh off the development line and hasn’t been audited yet. Please keep this in mind when exchanging data. In some countries, even a lol or a like can get you sent to jail. Berty is end-to-end encrypted - not even our developers could access your data, let alone corporations or governments. Just like blockchain technologies, Berty doesn’t pass your data through central servers - the place where internet service providers, hackers, and governments can intercept your data. Instead, Berty’s network is distributed, based on P2P direct messaging. Berty couldn’t care less about who you are. You don’t need to provide your real name, an email, or a date of birth. You don’t even need a SIM card! -
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QKSMS
A beautiful SMS messenger for Android
Fall in love with texting all over again with QKSMS! QKSMS is a beautiful, simple and customizable open source replacement to the stock messaging app on Android. It's got a clean, clutter-free intuitive design that lets you focus on what matters, plus millions of colors to choose from to make the theme of the entire app truly your own. QKSMS has some powerful features, including photo sharing, group chat, conversation blocking, message backup and restore and more. It's got everything you need from a text messaging app, plus all the fun features that make for a great text messaging experience. Simply put, QKSMS makes texting magical again, just the way it should be! -
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ChatSecure
ChatSecure is a free and open source encrypted chat client for iOS
ChatSecure is a free and open source messaging app that features OMEMO encryption and OTR encryption over XMPP. You can connect to your existing Google accounts or create new accounts on public XMPP servers (including via Tor), or even connect to your own server for extra security. Unlike other apps that keep you stuck in their walled garden, ChatSecure is fully interoperable with other clients that support OMEMO or OTR and XMPP, such as Conversations (Android), CoyIM (Desktop), and more. ChatSecure only uses well-known open-source cryptographic libraries to keep your conversations private. Other apps may make claims about "military grade" security but, without publicly auditable source code and verifiable end-to-end encryption, you cannot be truly safe. -
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Conversations
The very last word in instant messaging
Conversations is an open source Jabber/XMPP client for Android, designed to provide a unique and more freeing mobile messaging experience. XMPP is a federated protocol that can work with every XMPP server out there, giving you the freedom to choose a trustworthy server for yourself while still being able to chat with contacts from other servers. All communications are TLS encrypted and Conversations offers to enable one of two state of the art end-to-end encryption mechanisms, so you can be assured of the highest level of security in messaging. Conversations also offers plenty of unique features, such as image sharing, read markers, dynamic history loading and more. -
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Element Android
A glossy Matrix collaboration client for Android
Element Android is a glossy Matrix collaboration client for Android, based on a new Android SDK fully written in Kotlin. A total rewrite of Riot-Android, Element is an all-in-one secure chat app made possible through the open global Matrix network. It is a messenger that allows users to talk to anyone regardless of their app, while providing unparalleled privacy and security. It protects conversations from data-mining and ads with proper end-to-end encryption, so you can feel totally secure. Element is used by millions all over the world for their business, organizations, and even for personal and home use. It is part of the Matrix ecosystem, which is an open network for secure, decentralised communication governed by The Matrix.org Foundation.
