Linphone: Video and instant messaging
A long-running SIP client with encryption, which makes it a solid pick if you specifically want a standards-based VoIP and messaging tool rather than a walled-garden app. That same SIP heritage is the catch: it assumes you understand accounts and providers, so it is not the friendliest first messenger. Choose it for interoperable encrypted calling; look elsewhere for a one-tap consumer experience.
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Linphone alternatives
Free to use and modify, but anything you distribute that is built on it must also be open under the same license.
Permits
- Commercial use
- Modification
- Distribution
- Patent use
- Private use
Requires
- Disclose source
- Same license
- State changes
- License and copyright notice
Does not provide
- Liability cover
- Warranty
Why it matters: Strong copyleft keeps every distributed version open. A vendor cannot fold this into a closed product and ship it without releasing their changes.
Plain-language summary of the project's license, not legal advice. Read the full text for the exact terms.