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signalapp/signal-android

📈 Trending★ 28,819KotlinAudience · generalComplexity · 3/5ActiveLicenseSetup · hard

TLDR

Official Signal Android app for private messaging with end-to-end encryption built in by default, texts, calls, and video all encrypted so only you and the recipient can read them.

Mindmap

mindmap
  root((Signal Android))
    What it does
      Text messaging
      Voice calls
      Video calls
      Group chats
    Privacy features
      End-to-end encryption
      No server access
      Always on by default
    How to get it
      Google Play Store
      Direct download
      Open source code
    Who uses it
      Journalists
      Activists
      Privacy conscious users
    Tech stack
      Kotlin
      Android platform

Things people build with this

USE CASE 1

Send private text messages and make encrypted calls without worrying about your conversations being intercepted or stored by third parties.

USE CASE 2

Organize group chats with friends, family, or colleagues where all messages are encrypted end-to-end by default.

USE CASE 3

Make high-quality voice and video calls over WiFi or mobile data with the same privacy guarantees as text messages.

USE CASE 4

Verify the privacy claims yourself by reading the open-source code to confirm no backdoors or data collection exist.

Tech stack

KotlinAndroid

Getting it running

Difficulty · hard Time to first run · 1day+

Requires Android SDK setup, Gradle build system, and Signal's proprietary build infrastructure; compiling from source is complex.

GNU AGPLv3: use freely and modify, but any modified versions must also be open-source and distributed under the same license.

In plain English

Signal Android is the official open-source Android app for the Signal private messaging service. Signal lets you send messages, make voice calls, and have video calls over your phone's internet connection (WiFi or mobile data) with end-to-end encryption, meaning only you and the person you're talking to can read your messages, not Signal's servers or any third party. The app is designed around the idea that strong privacy should be the default, not an optional setting you have to dig for. You don't need to change any settings or flip any switches, the encryption is always on. It handles text messages, high-quality audio calls, HD video calls, and group chats. You would use this if you care about the privacy of your communications and want an alternative to standard SMS or other messaging apps that may store or have access to your conversation content. It's popular with journalists, privacy-conscious individuals, activists, and anyone who wants to keep their conversations confidential. The app is built in Kotlin (Android's primary programming language) and is available through the Google Play Store or as a direct download from signal.org. The source code is open, meaning anyone can inspect how it works and verify the privacy claims. The project is licensed under the GNU AGPLv3, which means any modified versions must also be open-source.

Copy-paste prompts

Prompt 1
How do I set up Signal Android on my phone and start messaging someone securely?
Prompt 2
What makes Signal's encryption different from other messaging apps, and how do I know my messages are actually private?
Prompt 3
Can I use Signal for group chats, and are group messages encrypted the same way as one-on-one messages?
Prompt 4
I want to build a messaging app with similar privacy features, what can I learn from Signal's open-source code?
Prompt 5
How do I verify that Signal isn't collecting my data by reviewing the source code myself?
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Generated 2026-05-18 · Model: sonnet-4-6 · Verify against the repo before relying on details.