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Viber vs Signal: catalog facts
Viber	Signal
Free Free to download and use for messages and calls.	Free Free; developed by a nonprofit funded by grants and donations
Android	Android, iOS, Windows, macOS, Linux
Voice and video calls plus group chats Chats sync between mobile and desktop	End-to-end encryption on every message and call using the open source Signal Protocol No ads, affiliate marketers or tracking
Proprietary and centrally run Communities and stickers add clutter for people who only want chat	Requires a phone number that can receive an SMS or phone call to register Desktop app requires Signal to be installed on a phone first
Downloadable app	Downloadable app
Closed source	Open source
License not stated	License: AGPL-3.0
Not stated if an account is needed	Account needed
Needs internet	Needs internet
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 20, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.