A complete, modular, and open-source server suite.
Based on the SIP telecommunication protocol
Deploy your VoIP and instant messaging service or enhance your connected devices
Flexisip easily integrates into your SIP infrastructure to meet various needs.
With the Flexisip server suite, create your own cloud service based on the SIP telecommunications protocol, add instant messaging, video conferencing, and push notifications to your service, or even integrate an embedded server into your connected hardware.
Access all the necessary features to deploy your own unified communication solution, optimized for mobile environments.
A complete SIP server for real-time communications
To deploy a unified communication service with calling, chat, and video conferencing features.
Flexisip modules provide advanced audio/video calling, instant messaging with file sharing, and video meetings.
These services can be deployed on machines of your choice, on-site or with a hosting provider. With high availability mechanisms and load balancing, Flexisip is particularly well-suited for deploying services targeting a large number of users.
Compatible with other SIP systems
To enhance your existing VoIP platform with unified communication features.
The Flexisip server suite can be deployed alongside an existing SIP service, such as Asterisk, FreeSWITCH, or Mitel.
Thanks to support for recent standards – including numerous SIP protocol extensions – Flexisip can adapt to the constraints of your current systems.
Gradually migrate your users to a fully software-based solution and add new features without losing the benefits of the platforms you have already deployed.
Integrable into small devices
To add internet audio and video calling features to your embedded products.
Thanks to its modular architecture and minimal dependencies, Flexisip runs efficiently on small embedded systems, such as Raspberry Pi.
Flexisip supports IoT-specific features, like Early Media Call Forking, which allows you to see the caller’s video before accepting the call.
Many clients, particularly in intercom and access control systems, use Flexisip for these applications.
Push Notification Gateway
To reliably notify your users of incoming calls and messages on smartphones.
On mobile platforms, push notification systems are presented as efficient and highly reliable methods for receiving information when the phone’s screen is off or when the VoIP or messaging application is running in the background.
The Push Gateway mode is a specific operating mode of Flexisip, developed to robustly route incoming SIP calls or text messages to Apple and Google smartphones and tablets. It can be integrated with existing SIP infrastructures that do not support push notifications.
Software architecture and features
The Flexisip server suite enables account management, conferencing, and telephony integration.
The Flexisip suite consists of a set of server software based on the SIP protocol and written in modern C++ language. It includes a SIP account manager, a proxy, a presence server, a conference server for group calls and multi-party text conversations, as well as a B2BUA module for gatewaying to the PSTN network and connecting to traditional telephony.
The source code is available under two projects: Flexisip (proxy, presence server, conference server, B2BUA) and Flexisip Account Manager (the SIP account manager).
SIP proxy
Push notifications for mobile platforms
Presence server
Chat and conference server
SIP/PSTN bridge
SIP account manager
Flexisip proxy
All traffic passes through the proxy module, which serves as the entry and exit point for SIP communications. It is responsible for the following tasks:
- Call routing
- Media relay with support for ICE/STUN/TURN
- Sending push notification requests to Apple and Google services
- Secure user authentication (via Digest, TLS client certificates, OAuth – OpenID Connect)
Flexisip Push Gateway
Push notifications allow VoIP calls or incoming messages to be delivered to mobile platforms when the app is not active in the foreground or when the phone screen is turned off. Flexisip proxy supports RFC 8599 and the latest requirements for push notification services from Apple (APNs) and Google (Firebase).
For organizations that have already selected a third-party SIP server that does not support push notifications, Flexisip can be deployed in a “Push Gateway” mode. This enables the addition of push notification support to these SIP infrastructures while allowing the existing server to manage the SIP traffic.
Flexisip presence
- Real-time user presence status
- Intelligent address book (identifying which numbers in the user directory are reachable via the service)
- Sharing of predefined contact lists
Flexisip conference
- Conference session and discussion group management
- Participant synchronization
- Management of multiple devices per user (multi-device)
- Event notifications (joined, left, etc.)
Flexisip B2BUA
Flexisip B2BUA enables the connection of a SIP network with a PSTN gateway or a SIP trunking service provided by a VoIP operator.
- Interconnection of SIP accounts with virtual numbers
- Incoming and outgoing calls between a SIP number and a traditional phone line (mobile number, landline, etc.)
- This module also offers media codec transcoding and encryption methods.
Note: We do not provide PSTN lines or virtual numbers.
Flexisip account manager
This software offers several key components for creating a secure user account management system. It is also the recommended tool for deploying the MySQL account database used by the Flexisip proxy.
Account Management API (FlexiAPI)
FlexiAPI is a REST API for managing user accounts:
- Account creation and management (editing, activation, deletion, changing email, etc.)
- Identity management
- Secure authentication
- Generation of dynamic configuration files and association of contact lists per user
For example, it allows adding SIP account management features to an existing administration platform.
Remote Configuration Server
This component generates configuration files compatible with Linphone clients. The end user only needs to scan a QR code or click a link received by email for the settings defined in the configuration file to be automatically applied to the application.
You can choose between static configuration (the same settings for all users) or dynamic configuration (a personalized configuration file per user).
Web Platform for SIP Service Administration
This online interface allows you to manage your user base and your service based on the Flexisip server:
- Account management
- Peering accounts with virtual numbers
- Enabling/disabling features by user group
- Affiliation of contact lists
- Service usage statistics
- Alert systems to facilitate server monitoring
Test all Flexisip features through our online SIP service!
Our online SIP service allows Linphone users to communicate with each other for free.
Not convinced by Flexisip yet? Create test accounts and try out the features you can benefit from on your own unified communication service in Linphone.
Modularity
Deploy only the modules that manage the features you need.
Scalability
Opt for a cluster deployment with high availability and load balancing.
Why choose the Flexisip SIP server
Developed in France
Flexisip is developed and maintained by our teams in Grenoble. Choose a sovereign solution!
Open source
100% of the source code is open source! Rely on transparency and reliability.
Licensing model
Choose between open-source or proprietary licensing.
Linphone 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
Flexisip 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 trust Flexisip
Have a project? Contact us!
Our Flexisip experts will be able to answer your questions about the software and help you define the server infrastructure best suited to your needs.
Discover our latest news
Improvements in interconnection with PSTN networks thanks to Flexisip B2BUA
To address the need for interconnecting a SIP network for enriched communication (voice, video, instant messaging,...
The release of Flexisip 2.4 is approaching!
Flexisip 2.4 is currently in preparation and will be ready for deployment by the end of...
Evolution of FlexiSIP Account Manager
Users are at the core of any service, as without them, the service has no purpose....
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