SDK SIP for VoIP, Instant Messaging, and Conferencing
Open source, cross-platform, and multi-language
Easily and quickly develop your internet communication applications
Using the VoIP SDK on which Linphone applications are based!
Liblinphone is a high-level open-source library that integrates all audio/video call (VoIP, video), conferencing, and instant messaging features through a single cross-platform API based on the SIP telecommunication protocol.
Find all the features you need to develop your own unified communication application, optimised for both mobile and desktop environments.
Easy integration into your mobile and desktop applications
To develop your softphone or add VoIP call or IM features to your applications.
Liblinphone brings together all real-time communication features (audio/video calls, instant messaging, video conferencing) into a single API. Optimised for mobile application development, it integrates easily into your IDEs via Maven and Cocoapod.
To simplify the work of multi-platform developers, our SDK provides wrappers in various languages: C/C++, C#, Python, Java/Kotlin, and Swift.
Prefer using a cross-platform framework? Liblinphone is compatible with MaUI.
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Audio and video call quality is our core expertise
We have been developing the media stream management engine of our VoIP SDK in-house for over 20 years.
We continuously invest in R&D to innovate in optimising audio and video call quality:
Integration of modern HD codecs, including for video: AV1, H265, H264
Innovative algorithms for dynamic media stream adaptation to network conditions
Optimal transmission quality through the use of advanced standards such as Flexible Forward Error Correction and RTCP feedback
Software or hardware echo cancellation depending on the hardware used
Optimised for the embedded world
To add voice and video call features to your connected devices.
Many manufacturers of intercom systems, access control, and connected devices have chosen Liblinphone as their SIP user agent.
Liblinphone easily integrates into small embedded devices running Linux, thanks to Yocto recipes. The SDK size can be significantly optimised at compile time by removing unnecessary features and dependencies.
Features
The Liblinphone library has been developed by our teams since 2001 and is fully compliant with the SIP standard (RFC 3261). New features are regularly added, and we are always looking to incorporate the latest innovations in audio and video quality, updates to the SIP standard, and new requirements for supported platforms.
Some of the features developed in our software are funded by our clients. Feel free to contact us!
HD audio calls
Opus codec for high-quality VoIP calls
Support for codecs optimised for traditional telephony: G729, G711
Patented jitter adaptation algorithm
Echo cancellation (software and hardware)
HD video calls
Support for AV1, H264, and H265 codecs
Dynamic network bitrate adaptation algorithm
Forward Error Correction (FEC)
Video codec selection based on hardware capabilities
Advanced call features
Call hold and resume
Management of multiple concurrent calls
Blind and attended call transfer
Call recording (audio/video)
Instant Messaging
1-to-1 and group (aiming for the RCS standard)
File sharing (images, videos, documents, etc.)
Ephemeral messages
Voice messages and reactions
Group calls and meetings
Group calls with up to 50 participants
Scheduling meetings with invitation sending
Instant Messaging
Screen sharing
Optimised NAT traversal
ICE
STUN
TURN
Secure authentication
Digest (SHA-265 or MD5)
Bearer (OAuth2 – OpenID Connect)
Via TLS client certificates
End-to-end encryption (E2E)
Support for SRTP-SDES, DTLS-SRTP, and ZRTP protocols
Detection of man-in-the-middle attacks with ZRTP
End-to-end encryption for all types of exchanges, including group conversations
Post quantum encryption
Liblinphone is the first open-source VoIP library to integrate post-quantum encryption, thanks to the Cristals-KYBER algorithm.
Test Linphone to get a preview of the features offered by Liblinphone!
Liblinphone is the VoIP SDK on which Linphone applications are based. While we have sometimes had to make default choices in Linphone, whereas Liblinphone offers more flexibility, Linphone applications provide a good overview of the type of VoIP and IM client that Liblinphone allows you to develop.
Software Architecture
Developing telecommunication client software requires two main components: one to manage media streams (audio and video packets, encoding and decoding of exchanged streams) and the other to handle signalling (call routing, ringing, call acceptance).
Liblinphone combines these two components (Mediastreamer2 and Belle-SIP) through a single API to make development easier, even for those who are not telecommunication experts.
Liblinphone also provides a consistent API for developing applications in various languages, with wrappers for Python, C, C#, C++, Java, and Swift.
Binaries or source code, the choice is yours
Looking to integrate Liblinphone into a closed-source application? Our source code licences are here for that.
100% of Liblinphone’s source code is open source. You can modify and compile it freely.
However, most users of our SDK prefer to integrate our libraries in binary form. With Maven and Cocoapod, integration into Xcode and Android Studio is made easy.
Only one API to use
To add all real-time communication features to your apps
Developed in France
Software created and maintained by our teams in Grenoble. Choose a sovereign solution!
Why choose the Linphone SDK?
Complete stack control
We develop the media streaming engine and the SIP stack in-house.
Open source
100% of the source code is open! Invest in transparency and reliability.
Licensing model
Choose between an open-source license or a proprietary license.
Liblinphone is available under a dual licence. Our proprietary licences allow you to modify the source code while keeping your modifications closed-source.
Open source license
Liblinphone can be integrated into your project under the terms of the GNU Affero GPLv3 open-source license.
Services
Development of new features
Finance the development of new features or adapt Linphone to your specific requirements.
They chose the Liblinphone VoIP SDK to develop their product
4Com
4Com PLC was founded in 1999 with the aim of improving the communications services of the UK’s SME market. Since then, the company has grown to over 300 people and currently provides 10,000+ UK businesses with phone systems.
Beam Messenger
Beam Propulsion Lab Inc. offers a real-time communication application, called Beam Messenger, for instant typing and transmission of text.
Have a project? Contact us!
Fill out our contact form for more information about our software building blocks for VoIP, videoconferencing, and instant messaging.
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