Signal
Signal Foundation
Founded 2014 • Mountain View, California
Monthly Active Users
40M
Organization Type
Non-profit
Funding
$150M+
Source Code
Open Source
Key Features
Default E2E Encryption
All messages, calls, and media encrypted by default
Sealed Sender
Hide sender identity from even Signal servers
Disappearing Messages
Configurable auto-delete timers for all chats
Signal PIN
Account recovery without phone number exposure
Group Messaging
Encrypted group chats with up to 1000 members
Voice & Video Calls
HD quality calls with full encryption
Strengths & Weaknesses
Strengths
- Gold standard for privacy and security
- Open source with independent audits
- Non-profit with no advertising
- Minimal data collection
- Recommended by security experts
Weaknesses
- Small user base limits network effect
- No enterprise features or bots
- Requires phone number registration
- Limited customization options
- No multi-device without phone